Zotac is one of the major players in the SFF PC space, having launched ultra-compact form-factor machines even before NUCs took off. The growth in that segment has broadened the available market for their mini-PCs, allowing them to experiment with a wide variety of models for different use-cases.

Zotac markets their passively-cooled SFF under the 'C-series' tag. These 'nano' units used to adopt a NUC form-factor (100mm x 100mm) with similar chassis dimensions, which provided performance and thermal efficiency commensurate with their size. Starting with Intel's Kaby Lake-Refresh series, the company started adopting a larger form factor and added some platform features. Having reviewed the Core i7-8550U-based Zotac ZBOX CI660 nano in that generation in early 2019, we concluded that it was a promising HTPC platform, albeit with a few loose ends.

Comet Lake-U (CML-U) made it quite simple for vendors to take their KBL-R-U systems and perform a quick turn-around by just replacing the internal processor with the newer one without having to tinker too much with the board design. Zotac has done exactly that in the Zotac CI662 nano that we are looking at today.

Introduction and Product Impressions

Zotac introduced their line-up of passively cooled mini-PCs back in 2014, and has been continuously iterating on them over several generations of products from both Intel and AMD. Having realized the limitations of what the form-factor could achieve in the ZBOX CI523 nano (where the thermal design could sustain the rated TDP of the Skylake-U processor for only 10 minutes before throttling), Zotac went back to the drawing board and came up with a fully re-imagined design in the ZBOX CI660 nano. With a slightly larger footprint, the CI660 nano was able to handle a 25W cTDP-up for the integrated KBL-R U-series SiP before settling down to a sustained 15W package power consumption under continuous stress. Our main complaint about the CI660 nano was that it wasn't entirely noiseless due to coil whine (and some noises that appeared to be resulting from the heat-sink fins responding to variations in thermal load). That apart, the CI660 nano completely resolved the issues seen in the CI523 nano. This has prompted Zotac to release a CML-U version with the same chassis design and almost the same internals in the ZBOX CI662 nano.

Zotac's passively cooled CML-U series (the ZBOX CI6x2 nano) has three members - the CI622 nano comes with a Core i3-10110U processor, the CI642 nano sports a Core i5-10210U, and the flagship CI662 nano that we are reviewing today based on the Core i7-10510U. The specifications in terms of I/Os and internals of the three members are otherwise the same.

Zotac supplied us with a barebones version of the CI662 nano, and we opted to complete the build with a SK hynix Gold S31 1TB 2.5" SSD and a TeamGroup-SD4-2666 2x 8GB DDR4 SODIMM kit. After completing the review, we realized that the SODIMMs had been operating at 2400 MHz (the 2666 Mhz was a XMP profile) - however, given that we are looking at a low-power fanless PC using a U-series processor, we opted against repeating the benchmarks with a SODIMM kit running at 2666 MHz (Zotac indicates DDR4-2666/2400 as supported configurations in the product page for the CI662 nano). The specifications of our review configuration are summarized in the table below.

Zotac ZBOX CI662 nano Specifications
Processor	Intel Core i7-10510U Comet Lake-U, 4C/8T, 1.80 GHz (4.90 GHz), 14nm, 8MB L2+L3, 15W (10W-25W)
Memory	Team Group TEAMGROUP-SD4-2666 DDR4 SODIMM 18-16-16-39 @ 2400 MHz 2x8 GB
Graphics	Intel UHD Graphics
Disk Drive(s)	SK hynix Gold S31 (1 TB; 2.5" SATA III; SK hynix 72L 3D TLC) (SK hynix Quartz SH87830CC In-House Controller)
Networking	Intel Wireless-AC 9462 2x Realtek RTL8168/8111 Gigabit Ethernet Controller
Audio	3.5mm Headphone Jack Capable of 5.1/7.1 digital output with HD audio bitstreaming (HDMI)
Miscellaneous I/O Ports	2x USB 3.2 Gen 2 Type-C (10Gbps) 1x USB 3.2 Gen 1 Type-A (5Gbps) 4x USB 3.2 Gen 2 Type-A (10Gbps) 1x SDXC
Operating System	Retail unit is barebones, but we installed Windows 10 Enterprise 20H2 x64
Pricing (As configured)	USD 550 (barebones) USD 715 (as configured, No OS)
Full Specifications	Zotac ZBOX CI662 nano Specifications

The Zotac ZBOX CI662 nano kit doesn't come with any pre-installed OS, but does come with a read-only USB key containing the drivers. In any case, we ended up installing the latest drivers downloaded off Zotac's product support page. In addition to the main unit, the other components of the package include a 65 W (19V @ 3.42A) adapter, a US power cord, a VESA mount (along with the necessary screws), a single 2.4 GHz / 5 GHz antenna for the Wi-Fi feature, user's manual and a quick-start guide.

The external hardware appearance and build quality of the system, as well as the I/Os are essentially the same as the CI660 nano we looked at in 2019. The differentiating aspects (compared to other mini-PCs) continue to be the full-sized SDXC card slot and dual RJ-45 LAN ports. The honeycomb design of the chassis with liberal perforations allows for the heat drawn away by the heat sink to be convectively dissipated.

The rubber feet on the underside of the chassis can be removed without the use of a screwdriver (Zotac touts tool-less installation as a plus point for the system). Opening up the underside allows for the installation of a 2.5" SATA drie and DDR4 SODIMMs. The base itself has thermal pads mounted for the RAM sticks as well as the SSD.

The plastic film over the thermal pads need to be removed prior to finalizing the installation of components. The ASMedia ASM2142 daughterboard that enables the two USB 3.1 Gen 2 Type-C ports can also be seen adjoining the SODIMM slots.

BIOS Features

Zotac has a functional GUI-based BIOS interface. The gallery below brings out the various features in the BIOS.

The main screen provides system information at a glance. The OC section allows for enabling / disabling cores, activation of turbo modes and C-states, as well as controlling the Intel SpeedStep dynamic frequency scaling option. By default, the system makes beeping noises when starting up or rebooting - this can be turned off in the 'Features' section of the BIOS. Advanced options such as SGX (Software Guard Extensions) can also be controlled from here. The 'PC Health' section gives a view of the temperature and voltages in the system. ACPI settings are handled in the 'Power' section. The 'Boot' section allows configuration of boot order, selection of UEFI or legacy mode for the OS, fast boot control, secure boot configuration, etc. Single-time boot overriding is also possible.

Platform Analysis

Intel's Comet Lake-U processor has a wide variety of IO configurations, and we start with the configuration used on the ZBOX CI662 nano board by Zotac.

The SDXC card reader is enabled by a Realtek USB card reader controller. The two USB 3.2 Gen 2 (10Gbps) ports in the front are enabled by the ASMedia ASM2142 controller connecting to the built-in PCH through a PCIe 3.0 x4 link. The two Gigabit Ethernet controllers also take up a single PCIe 3.0 lane each. The Wireless-AC 9462 WLAN controller talks to the CML-U SiP using CNVi, while using one of the USB ports for Bluetooth functionality. The four Type-A ports in the rear are all USB 3.2 Gen 2 (10Gbps) directly from the built-in PCH. The single USB 3.2 Gen 1 Type-A port (marked helpfully by Zotac as USB 3.0 to differentiate from the USB 3.1 tag on the other USB ports) is also behind the same root hub as the other USB ports off the built-in PCH.

Benchmarks and Performance

In the table below, we have an overview of the various systems that we are comparing the Zotac ZBOX CI662 nano against. Note that they may not belong to the same market segment. The relevant configuration details of the machines are provided so that readers have an understanding of why some benchmark numbers are skewed for or against the Zotac ZBOX CI662 nano when we come to those sections.

Comparative PC Configurations
Aspect	Zotac ZBOX CI662 nano	Zotac ZBOX CI662 nanoIntel NUC8i5BEB (Akasa Turing)ECS LIVA Z3 PlusIntel NUC10i7FNH (Frost Canyon)Zotac ZBOX CI660 nanoECS LIVA Z2
CPU	Intel Core i7-10510U	Intel Core i7-10510U
GPU	Intel UHD Graphics	Intel UHD Graphics
RAM	Team Group TEAMGROUP-SD4-2666 DDR4 SODIMM 18-16-16-39 @ 2400 MHz 2x8 GB	Team Group TEAMGROUP-SD4-2666 DDR4 SODIMM 18-16-16-39 @ 2400 MHz 2x8 GB
Storage	SK hynix Gold S31 (1 TB; 2.5" SATA III; SK hynix 72L 3D TLC) (SK hynix Quartz SH87830CC In-House Controller)	SK hynix Gold S31 (1 TB; 2.5" SATA III; SK hynix 72L 3D TLC) (SK hynix Quartz SH87830CC In-House Controller)
Wi-Fi	Intel Wireless-AC 9462	Intel Wireless-AC 9462
Price (in USD, when built)	$550 (barebones) $715 (as configured / No OS)	$550 (barebones) $715 (as configured / No OS)

All of the above systems other than the ECS LIVA Z3 Plus and the Frost Canyon NUC are passively cooled. We include those two actively-cooled systems to get an idea of the performance of the CI662 nano against other Comet Lake-U mini-PCs. LIVA Z3 Plus Out of these systems. In the remainder of this review, we will first look at BAPCo's SYSmark 25, followed by various UL benchmarks and miscellaneous workloads. We also present some storage and networking performance numbers. A detailed look at the HTPC credentials of the system is followed by testing of the power consumption and thermal solution.

BAPCo SYSmark 25

The Zotac ZBOX CI662 nano was evaluated using our Fall 2018 test suite for small-form factor PCs. In the first section, we will be looking at SYSmark 25.

BAPCo's SYSmark 25 is an application-based benchmark that uses real-world applications to replay usage patterns of business users in the areas of productivity, creativity, and responsiveness. The 'Productivity Scenario' covers office-centric activities including word processing, spreadsheet usage, financial analysis, software development, application installation, file compression, and e-mail management. The 'Creativity Scenario' represents media-centric activities such as digital photo processing, AI and ML for face recognition in photos and videos for the purpose of content creation, etc. The 'Responsiveness Scenario' evaluates the ability of the system to react in a quick manner to user inputs in areas such as application and file launches, web browsing, and multi-tasking.

Scores are meant to be compared against a reference desktop (the SYSmark 25 calibration system, a Lenovo Thinkcenter M720q with a Core i5-8500T and 8GB of DDR4 memory to go with a 256GB M.2 NVMe SSD). The calibration system scores 1000 in each of the scenarios. A score of, say, 2000, would imply that the system under test is twice as fast as the reference system.

SYSmark 25 also adds energy measurement to the mix. A high score in the SYSmark benchmarks might be nice to have, but, potential customers also need to determine the balance between power consumption and the efficiency of the system. For example, in the average office scenario, it might not be worth purchasing a noisy and power-hungry PC just because it ends up with a 2000 score in the SYSmark 2014 SE benchmarks. In order to provide a balanced perspective, SYSmark 25 also allows vendors and decision makers to track the energy consumption during each workload. In the graphs below, we find the total energy consumed by the PC under test for a single iteration of each SYSmark 25 workload. For reference, the calibration system consumes 8.88 Wh for productivity, 10.81 Wh for creativity, and 19.69 Wh overall.

The raw scores are in line with the capabilities of the CPU used in the different systems, with the hexa-core Core i7-10710U in the Frost Canyon NUC outscoring the quad-core Core i7-10510U in the CI662 nano. The ECS LIVA Z3 also sports a 4C/8T processor, but the clock speeds are lower and the cache is also smaller, which makes it drop behind the CI662 nano. The energy numbers, on the other hand, do not look good for the CI 662 nano. This is a problem we observed in the CI 660 nano review also - the idle power consumption numbers being a bit too high. In the SYSmark 25 energy consumption numbers, it is also translating to quite a bit of extra energy being consumed in the process of completing the workloads.

UL Benchmarks - PCMark and 3DMark

This section deals with a selection of the UL Futuremark benchmarks - PCMark 10, PCMark 8, and 3DMark. While the first two evaluate the system as a whole, 3DMark focuses on the graphics capabilities.

PCMark 10

UL's PCMark 10 evaluates computing systems for various usage scenarios (generic / essential tasks such as web browsing and starting up applications, productivity tasks such as editing spreadsheets and documents, gaming, and digital content creation). We benchmarked select PCs with the PCMark 10 Extended profile and recorded the scores for various scenarios. These scores are heavily influenced by the CPU and GPU in the system, though the RAM and storage device also play a part. The power plan was set to Balanced for all the PCs while processing the PCMark 10 benchmark.

The performance numbers are very similar to the ones obtained for the CI660 nano. We do have additional passively-cooled PCs for comparison here - in terms of CPU prowess, the hexa-core configuration and high clock speeds help the CI662 nano outscore the Bean Canyon NUC in the Akasa Turing chassis. However, when it comes to workloads that rely on the GPU also (like gaming and content creation), the Iris Plus graphics in the DIY Bean Canyon / Akasa Turing kit pulls ahead by a big margin. This allows the overall score to be in favor of this DIY configuration.

PCMark 8

We continue to present PCMark 8 benchmark results (as those have more comparison points) while our PCMark 10 scores database for systems grows in size. PCMark 8 provides various usage scenarios (home, creative and work) and offers ways to benchmark both baseline (CPU-only) as well as OpenCL accelerated (CPU + GPU) performance. We benchmarked select PCs for the OpenCL accelerated performance in all three usage scenarios. These scores are heavily influenced by the CPU in the system. With OpenCL in the mix, the die is again loaded in favor of the DIY Bean Canyon / Akasa Turing kit with its better GPU for the home and creative workloads. However, productivity swings back in favor of the passively-cooled ZBOX configurations.

3DMark

UL's 3DMark comes with a diverse set of graphics workloads that target different Direct3D feature levels. Correspondingly, the rendering resolutions are also different. We use 3DMark 2.4.4264 to get an idea of the graphics capabilities of the system. In this section, we take a look at the performance of the Zotac ZBOX CI662 nano across the different 3DMark workloads.

3DMark Ice Storm

This workload has three levels of varying complexity - the vanilla Ice Storm, Ice Storm Unlimited, and Ice Storm Extreme. It is a cross-platform benchmark (which means that the scores can be compared across different tablets and smartphones as well). All three use DirectX 11 (feature level 9) / OpenGL ES 2.0. While the Extreme renders at 1920 x 1080, the other two render at 1280 x 720. The graphs below present the various Ice Storm worloads' numbers for different systems that we have evaluated.

UL 3DMark - Ice Storm Workloads

3DMark Cloud Gate

The Cloud Gate workload is meant for notebooks and typical home PCs, and uses DirectX 11 (feature level 10) to render frames at 1280 x 720. The graph below presents the overall score for the workload across all the systems that are being compared.

3DMark Sky Diver

The Sky Diver workload is meant for gaming notebooks and mid-range PCs, and uses DirectX 11 (feature level 11) to render frames at 1920 x 1080. The graph below presents the overall score for the workload across all the systems that are being compared.

3DMark Fire Strike Extreme

The Fire Strike benchmark has three workloads. The base version is meant for high-performance gaming PCs. Similar to Sky Diver, it uses DirectX 11 (feature level 11) to render frames at 1920 x 1080. The Ultra version targets 4K gaming system, and renders at 3840 x 2160. However, we only deal with the Extreme version in our benchmarking - It renders at 2560 x 1440, and targets multi-GPU systems and overclocked PCs. The graph below presents the overall score for the Fire Strike Extreme benchmark across all the systems that are being compared.

3DMark Time Spy

The Time Spy workload has two levels with different complexities. Both use DirectX 12 (feature level 11). However, the plain version targets high-performance gaming PCs with a 2560 x 1440 render resolution, while the Extreme version renders at 3840 x 2160 resolution. The graphs below present both numbers for all the systems that are being compared in this review.

UL 3DMark - Time Spy Workloads

3DMark Night Raid

The Night Raid workload is a DirectX 12 benchmark test. It is less demanding than Time Spy, and is optimized for integrated graphics. The graph below presents the overall score in this workload for different system configurations.

Scores broadly follow the trend of the Iris Plus GPU in the DIY Bean Canyon / Akasa Turing kit winning by huge margins. The CI660 nano and CI662 nano are pretty much neck-to-neck in most cases. The few in which the CI660 nano pulls ahead can be attributed to the faster DRAM used in the older configuration (DDR4-2666 vs DDR4-2400).

Miscellaneous Performance Metrics

This section looks at some of the other commonly used benchmarks representative of the performance of specific real-world applications.

3D Rendering - CINEBENCH

We use CINEBENCH R15 and R23 for 3D rendering evaluation. R15 provides three benchmark modes - OpenGL, single threaded and multi-threaded, while R23 provides only single and multi-threaded modes. Evaluation of different PC configurations in all supported modes provided us the following results.

Multi-threaded performance is broadly related to the core count, though the DIY configuration with higher TDP budget is also able to put in a good show. The OpenGL (GPU-dependent) performance is obviously in favor of the unit with the Iris Plus GPU. The R23 scores are in line with the clock speeds and core counts of the different CML-U SiPs used in the PCs.

x265 Benchmark

Next up, we have some video encoding benchmarks using x265 v2.8. The appropriate encoder executable is chosen based on the supported CPU features. In the first case, we encode 600 1080p YUV 4:2:0 frames into a 1080p30 HEVC Main-profile compatible video stream at 1 Mbps and record the average number of frames encoded per second.

Our second test case is 1200 4K YUV 4:2:0 frames getting encoded into a 4Kp60 HEVC Main10-profile video stream at 35 Mbps. The encoding FPS is recorded.

The CI662 nano seems a bit hampered by the slow DRAM, but otherwise matches the CI660 nano. Against the DIY Bean Canyon / Akasa Turing kit, the CI662 nano is at a disadvantage because of TDP limitations. The hexa-core Frost Canyon NUC takes the lead in both 8b and 10b encoding due to the large number of threads available to the encoder.

7-Zip

7-Zip is a very effective and efficient compression program, often beating out OpenCL accelerated commercial programs in benchmarks even while using just the CPU power. 7-Zip has a benchmarking program that provides tons of details regarding the underlying CPU's efficiency. In this subsection, we are interested in the compression and decompression rates when utilizing all the available threads for the LZMA algorithm.

Performance broadly follows the relative core count, clock speed, and DRAM speed ordering for the systems under consideration - and the CI662 nano marks its entry in the middle of the pack.

Cryptography Benchmarks

Cryptography has become an indispensable part of our interaction with computing systems. Almost all modern systems have some sort of hardware-acceleration for making cryptographic operations faster and more power efficient. In this sub-section, we look at two different real-world applications that may make use of this acceleration.

BitLocker is a Windows features that encrypts entire disk volumes. While drives that offer encryption capabilities are dealt with using that feature, most legacy systems and external drives have to use the host system implementation. Windows has no direct benchmark for BitLocker. However, we cooked up a BitLocker operation sequence to determine the adeptness of the system at handling BitLocker operations. We start off with a 2.5GB RAM drive in which a 2GB VHD (virtual hard disk) is created. This VHD is then mounted, and BitLocker is enabled on the volume. Once the BitLocker encryption process gets done, BitLocker is disabled. This triggers a decryption process. The times taken to complete the encryption and decryption are recorded. This process is repeated 25 times, and the average of the last 20 iterations is graphed below.

The CI662 nano, CI660 nano, DIY Bean Canyon NUC / Akasa Turing kit, and the Frost Canyon NUC perform very similarly in this benchmark, given that they are based on processors with the same microarchitecture. It is possible that the updates in Windows 10 20H2 have given the CI662 nano an edge (given that the benchmarks on the other systems were run with either Windows 10 1903 or Windows 10 1909).

Creation of secure archives is best done through the use of AES-256 as the encryption method while password protecting ZIP files. We re-use the benchmark mode of 7-Zip to determine the AES256-CBC encryption and decryption rates using pure software as well as AES-NI. Note that the 7-Zip benchmark uses a 48KB buffer for this purpose.

The 7-zip cryptography benchmark numbers are in-line with the results for plain archiving. DRAM speed shouldn't be much of a factor here, as the buffer should easily fit into the cache. 

Yet another cryptography application is secure network communication. OpenSSL can take advantage of the acceleration provided by the host system to make operations faster. It also has a benchmark mode that can use varying buffer sizes. We recorded the processing rate for a 8KB buffer using the hardware-accelerated AES256-CBC-HAC-SHA1 feature.

The performance of the different systems for OpenSSL seem to be fairly similar to each other, with the CI662 nano in the middle of the pack.

Agisoft Photoscan

Agisoft PhotoScan is a commercial program that converts 2D images into 3D point maps, meshes and textures. The program designers sent us a command line version in order to evaluate the efficiency of various systems that go under our review scanner. The command line version has two benchmark modes, one using the CPU and the other using both the CPU and GPU (via OpenCL). We present the results from our evaluation using the CPU mode only. The benchmark (v1.3) takes 84 photographs and does four stages of computation:

• Stage 1: Align Photographs (capable of OpenCL acceleration)
• Stage 2: Build Point Cloud (capable of OpenCL acceleration)
• Stage 3: Build Mesh
• Stage 4: Build Textures

We record the time taken for each stage. Since various elements of the software are single threaded, and others multithreaded, it is interesting to record the effects of CPU generations, speeds, number of cores, and DRAM parameters using this software.

The CI662 nano is slightly handicapped by the slower DRAM speed compared to the CI660 nano. The trend in the results are indicative of the faster CPUs with higher core counts performing better.

Dolphin Emulator

Wrapping up our application benchmark numbers is the new Dolphin Emulator (v5) benchmark mode results. 

This is again a test of the CPU capabilities - the CI660 nano and the CI662 nano perform very similar to each other, and the faster Core i7-10710U with two extra cores in the Frost Canyon NUC makes it come out at the top of the pack.

Storage and Networking Performance

Networking and storage are two major aspects which influence our experience with any computing system. This section presents results from our evaluation of these aspects in the Zotac ZBOX CI662 nano. On the storage side, one option would be repetition of our strenuous SSD review tests on the drive(s) in the PC. Fortunately, to avoid that overkill, UL PCMark 10 has a Full System Drive Benchmark storage test certain common workloads such as booting, loading games, and document processing are replayed on the target drive. The average access times and bandwidth numbers are recorded for each trace and the overall numbers contribute to a benchmark score. For older systems, we have scores from the PCMark 8 storage bench (which we continue to process on newer machines as we build up the database of PCMark 10 storage bench results).

In case of single drive systems, we attempt to allocate 180GB to the primary partition, and leave the remaining space on the drive as a secondary partition. For dual-drive systems, the OS drive is the primary drive, while the other is categorized as the secondary one. Since PCMark 10 requires 80GB of free space at the minimum for processing the Full System Drive Benchmark, we are able to process the benchmark on both the primary and secondary drive in only some of the evaluated systems. The results are presented below.

The PCMark 8 storage bench doesn't indicate much difference between the different drives (SATA or NVMe) in the subsystem score, but the bandwidth numbers clearly differentiate between the SATA and NVMe-class drives. The CI6xx nano series doesn't support NVMe drives - only 2.5" drives are supported, and we have one of the best in that class used in the CI662 nano review sample.

The SK hynix Gold S31 is the only SATA SSD to be subject to the PCMark 10 Storage Bench as part of our systems evaluation process. We know it is not meant to produce the same level of performance as the NVMe drives used in the Frost Canyon NUC or the DIY Bean Canyon NUC / Akasa Turing kit, but it still returns respectable access times that are essential for a responsive system.

On the networking side, we restricted ourselves to the evaluation of the WLAN component. Our standard test router is the Netgear Nighthawk AX12 RAX120 configured with both 2.4 GHz and 5 GHz networks. The router is placed approximately 11 ft. away with a direct line-of-sight to the PC under test. A wired client (Zotac MI553, with an Akitio T3-10G NBASE-T Thunderbolt 3 adapter) is connected to the 5GbE port of the RAX120 and serves as one endpoint for iperf evaluation.

The RAX120 can be explicitly configured to connect over a DFS channel. This works in the absence of any radar presence in the vicinity. We configured the router to operate in Channel 64 (DFS) after ensuring that no nearby wireless networks were operating in that channel (in order to avoid benchmarking interference as much as possible). In such a scenario, the Zotac ZBOX CI662 nano connected with the following parameters.

A script to run iPerf3 with 1, 2, 4, 8, and 16 parallel streams between the Zotac ZBOX CI662 nano and the Zotac ZBOX MI553 was processed - the first set for TX alone, followed by another set for RX, and finally a third set with bidirectional traffic.

Due to the 433 Mbps single-stream 802.11ac configuration, we can expect around 370 Mbps of best-case throughput via the Wireless-AC 9462 in the Zotac ZBOX CI662 nano. The table below presents the iPerf3 benchmark results obtained in the above testing scenario.

Wireless Bandwidth - TCP Traffic - Zotac ZBOX CI662 nano (iPerf3 Throughput in Gbps)
Stream Count	80 MHz Wi-Fi 5 (DFS Channel)
	TX	RX
1	0.340	-
2	0.369	-
4	0.370	-
8	0.369	-
16	0.366	-
1	-	0.360
2	-	0.359
4	-	0.358
8	-	0.359
16	-	0.359
1	0.102	0.264
2	0.030	0.332
4	0.142	0.229
8	0.106	0.261
16	0.133	0.236

The numbers presented above are slightly lesser than the average segment bandwidths noted, as the data in the graph is computed from the network interface's counters, while iPerf reports results based only on the traffic sent by it alone.

HTPC Credentials - Display Outputs and Streaming Capabilities

The Zotac ZBOX CI662 nano comes with two display outputs - a HDMI 2.0a port with 4Kp60 HDR support, and a full-sized DisplayPort (DP 1.2a) also with 4Kp60 HDR support. From a HTPC use-case perspective, HDMI 2.0a port with HDCP 2.2 support fits the bill for viewing protected content such as 4K Netflix streams and theoretically, UltraHD Blu-rays too.

Supporting the display of high-resolution protected video content is a requirement for even a casual HTPC user. In addition, HTPC enthusiasts also want their systems to support refresh rates that either match or be an integral multiple of the frame rate of the video being displayed. Most displays / AVRs are able to transmit the supported refresh rates to the PC using the EDID metadata. In some cases, the desired refresh rate might be missing in the list of supported modes.

Display Resolutions and Refresh Rates

Our evaluation of the Zotac ZBOX CI662 nano as a HTPC was done using the native HDMI output connected to a TCL 55P607 4K HDR TV via a Denon AVR-X3400H AV receiver. Prior to that, the system was connected to a LG 34WK96U-W to determine behavior with a display supporting all possible refresh rates of interest - including both NTSC and PAL - with HDR enabled. Unlike the CI660 nano, we were able to activate HDR with both displays using the CI662 nano.

We tested out various display refresh rates ranging from 23.976 Hz to 59.94 Hz. Of particular interest is the 23.976 Hz (23p) setting, which Intel used to have trouble with in the pre-Broadwell days. The CI662 nano is one of the first PCs we have evaluated in a long time that was not able to provide an accurate 23.976 Hz display output refresh rate.

The gallery below presents screenshots from the other refresh rates that were tested. Unfortunately, the offset seen for 23.976 Hz also seems to translate over to other desired refresh rates.

YouTube Streaming

The move to 4K, and the need to evaluate HDR support have made us choose Mystery Box's Peru 8K HDR 60FPS video as our test sample moving forward. On PCs running Windows, it is recommended that HDR streaming videos be viewed using the Microsoft Edge browser after putting the desktop in HDR mode.

The YouTube server provides a VP9 Profile 2 stream as it is supported by the GPU. For some reason, the optimal encode delivered by the server had a 1440p resolution. Forcing the resolution to native 2160p resulted in frequent dropped frames (around 2955 out of 7708 frames at the time of the above screenshot).

Various metrics of interest such as GPU usage and at-wall power consumption were recorded for the first four minutes of the playback of the above video. The numbers are graphed below.

The frequent jumps in GPU usage to nearly 100% point to the reason behind the dropped frames. Shifting the display to non-HDR mode resulted in a VP9 stream getting streamed.

The CI662 nano has no trouble playing back the non-HDR 4K stream.

The at-wall power consumption in the steady state averaged slightly north of 20W as the media engine usage remained below 80%.

HTPC Credentials - Local Media Playback and Video Processing

Evaluation of local media playback and video processing is done by playing back files encompassing a range of relevant codecs, containers, resolutions, and frame rates. A note of the efficiency is also made by tracking GPU usage and power consumption of the system at the wall. Users have their own preference for the playback software / decoder / renderer, and our aim is to have numbers representative of commonly encountered scenarios. Towards this, we played back the test streams using the following combinations:

• MPC-HC x64 1.8.5 + LAV Video Decoder (DXVA2 Native) + Enhanced Video Renderer - Custom Presenter (EVR-CP)
• VLC 3.0.8
• Kodi 18.9

The usage of madVR with integrated GPUs is not a common use-case, and we have decided to forsake testing thoe usual madVR configurations in this review.

Fourteen test streams comprising of various codecs and frame rates (each of 90s duration) were played back from the local disk with an interval of 30 seconds in-between. Various metrics including GPU usage and at-wall power consumption were recorded during the course of this playback. Prior to looking at the metrics, a quick summary of the decoding capabilities of the GPU is useful to have for context.

We have seen this in many Comet Lake reviews over the past few months, and there are no surprises with the evaluated drivers - all codecs except AV1 are supported at their commonly-used resolutions.

VLC and Kodi

VLC is the playback software of choice for the average PC user who doesn't need a ten-foot UI. Its install-and-play simplicity has made it extremely popular. Over the years, the software has gained the ability to take advantage of various hardware acceleration options. Kodi, on the other hand, has a ten-foot UI making it the perfect open-source software for dedicated HTPCs. Support for add-ons make it very extensible and capable of customization. We played back our test files using the default VLC and Kodi configurations, and recorded the following metrics.

Video Playback Efficiency - VLC and Kodi

Both VLC and Kodi have no issues in playing back all streams successfully except for the AV1 clip. Kodi is a bit more leaner on the resource consumption side compared to VLC. Average power consumption at the wall is less than 35W even for high-resolution high-frame rate interlaced clips.

MPC-HC

MPC-HC offers an easy way to test out different combinations of decoders and renderers. The first configuration we evaluated is the default post-install scenario, with only the in-built LAV Video Decoder forced to DXVA2 Native mode. The metrics collected during the playback of the test files using the above configuration are presented below.

Though D3D usage touched close to 100% for the 60fps clips, we found no evidence of dropped frames during playback - EVR-CP doesn't give statistics as readily as madVR does, and we could only rely on visual evidence for this. In any case, we can recommend the usage of Kodi, VLC, and MPC-HC (in that order) for playing back media files on the CI662 nano.

UHD Blu-ray Playback

The ability to enable SGX in the BIOS and also use a HDCP 2.2 4Kp60 display successfully with the CI662 nano point to an ideal UltraHD Blu-ray playback platform. After having reviewed a string of PCs on which this feature couldn't be tested, we finally hoped to get UHD-BR working on a new unit.

Unfortunately, despite enabling SGX (either explicitly or setting it to 'software controlled') and reinstalling the Management Engine components / drivers multiple times as directed, the Ultra HD Blu-ray Advisor tool refused to pass the configuration as capable of UHD-BR playback. After repeated trials, we gave up on this exercise - to the point that we no longer want to test future systems for UHD-BR compatibility. The user experience resulting from the Blu-ray Disc Association's DRM requirements is sub-optimal at best, and completely horrendous at worst.

Power Consumption and Thermal Performance

The power consumption at the wall was measured with a 4Kp60 non-HDR display being driven through the HDMI port. In the graphs below, we compare the idle and load power of the Zotac ZBOX CI662 nano with other low power PCs evaluated before. For load power consumption, we ran the AIDA64 System Stability Test as well as our custom stress test with Prime95 and Furmark, and noted the maximum power consumption at the wall.

The power consumption profile of the CI662 nano is essentially the same as that of the CI660 nano. The idling power is way too high for a system that uses a SATA SSD and DDR4-2400 DRAM. Given that other CML-U systems are able to have lower idling power numbers, Zotac should definitely go back and review their default BIOS configuration to determine the cause of this behavior.

Our thermal stress routine starts with the system at idle, followed by four stages of different system loading profiles using the AIDA64 System Stability Test (each of 30 minutes duration). In the first stage, we stress the CPU, caches and RAM. In the second stage, we add the GPU to the above list. In the third stage, we stress the GPU standalone. In the final stage, we stress all the system components (including the disks). Beyond this, we leave the unit idle in order to determine how quickly the various temperatures in the system can come back to normal idling range. The various clocks, temperatures and power consumption numbers for the system during the above routine are presented in the graphs below.

Zotac ZBOX CI662 nano System Loading with the AIDA64 System Stability Test

The frequencies of the CPU and GPU are at or above the rated clocks throughout the stress routine. The temperatures of different components are also in the safe zone - less than 80C for the CPU package and around 60C for the SSD (when it is subject to stress). The package power is 15W throughout the testing, and the cooling solution has no trouble keeping up with that - just the same as what we saw in the CI660 nano review.

Zotac ZBOX CI662 nano System Loading with Prime95 and Furmark

Under artificially stressful workloads like Prime95 and Furmark, the GPU is able to meet the rated clocks, but the CPU adjusts itself in simultaneous loading scenarios to ensure that the package power consumption doesn't go beyond 15W. Temperatures do not go beyond 80C for these workloads either.

The thermal solution employed by Zotac in the C-series since mid-2018 is quite effective in handling 15W TDP processors, as we noted in the CI660 nano review earlier and the CI662 nano above. The package temperature is maintained well below the 100C junction temperature even under sustained stressful workloads.

Miscellaneous Aspects and Concluding Remarks

Prior to wrapping up this review, there are few different aspects of the Zotac CI662 nano that need to be addressed. These include external thermal profile, pricing and value proposition, comparisons against similar systems in the market, and things Zotac could address in future C-series systems.

External Thermal Profile

The core thermal solution employed in the ZBOX CI662 nano is the huge heat-sink that completely envelopes the board except for the underside (to allow installation of a 2.5" drive and the DDR4 SODIMMs). Unlike other passively-cooled PCs, it is not possible to directly touch the heat-sink by accident. The heat in the fins are drawn out by convection through the plastic chassis with plenty of perforations in a honeycomb pattern. The plastic casing itself doesn't get very hot. The case also has either a flat profile or rounded edges around the spots where it is usually held to access the I/O ports or power button.

After the stressful segments of our custom stress test were done, we immediately took thermal photographs using a FLIR One camera. The plastic spots in the chassis on the sides were only around 35C, though the thermal camera was able to capture temperatures of up to 68C directly on top of the case.

Additional thermal photographs with temperature ranges embedded are available in the gallery below.

Overall, the design of the system is such that it is safe enough to have within touching distance on a desk and not have to worry about accidentally burning one's hands. Access to the I/O ports is also made safe by the lack of sharp edges in the normally-accessed parts of the chassis.

Pricing and Value Proposition

The Zotac ZBOX CI662 nano has a MSRP of $550. This is $75 lesser than the $625 at which the ZBOX CI660 nano flagship of the previous generation was introduced. Perhaps, economies of scale have kicked in, as the chassis design for the two units are essentially the same. Though we pushed the price of our build to $715, it is possible to use a judicious set of components to complete the build for as low as $650. For a ready-to-use passively cooled mini-PC, this is good value for money.

It is possible to build a passively cooled version of a Frost Canyon NUC with an after-market chassis for around the same or slightly higher cost - but the efforts needed to assemble the passively-cooled case may be too time-consuming for many customers. Pre-built passively-cooled NUCs also carry a significant premium. An almost ready-to-use mini-PC like the ZBOX CI662 nano fits this target market perfectly. Relatively speaking, $550 is an affordable price tag for such a system.

Closing Thoughts

One of our primary complaints about the ZBOX CI660 nano was the coil whine / heat-sink noise - thankfully, we didn't encounter that at all in our review sample of the ZBOX CI662 nano. For all practical purposes, our review sample was a noiseless one. One of the contributing aspects to this could be the alteration of the power consumption behavior under load. In the CI660 nano, we saw the system start out with a 25W package power budget before ramping it down to the 15W point for which the thermal design is more suited. In the CI662 nano, the PL1 and PL2 limits are set such that the system ramps down to 15W quite quickly. This could also be one of the reasons why the CI660 nano churned out slightly better benchmark numbers in a few workloads compared to the CI662 nano. Sustained performance was pretty much the same for the CI662 nano and the CI660 nano.

Another aspect that ended up getting fixed (at least, in our testing environment) was HDR. We were able to get HDR working with both the HDMI and DisplayPort outputs in the CI662 nano. The system is good enough for casual HTPC use, though enthusiasts might bemoan the lack of accurate display output refresh rates and the inability to get UHD Blu-ray playback working properly (consumers might have better luck with their samples than what I had with mine on both aspects). The system doesn't seem particularly powerful for 4K HDR streaming at 60 fps, though similarly encoded local media files played back without issues (pointing to issues probably related to the browser or drivers).

Zotac still needs to fix up the curious case of high idle power consumption numbers compared to similar PCs in the market. They also need to replace the 2.5" slot with a M.2 NVMe SSD slot in future iterations - perhaps borrowing PCIe lanes direct from the CPU instead of relying on the ones from the PCH.

Zotac's value additions in terms of two extra USB 3.2 Gen 2 (10 Gbps) ports using the ASMedia ASM2142 controller is praiseworthy - though with the PCH also providing four such ports in the rear panel of the unit, we would have preferred these to be USB 3.2 Gen 2x2 (20 Gbps) ones. Zotac also provides dual LAN ports for a variety of use-cases - something that is not available in systems like the Frost Canyon NUC without using an external Thunderbolt 3/USB dock.

Overall, it can be said that the Zotac ZBOX CI662 nano is on the affordable side of the spectrum for fanless systems. The platform continues to maintain the promise it had when launched with the CI660 nano, and the core upgrades done by Intel in the follow-up to Comet Lake-U will also help Zotac to innovate further in the future. In addition to a M.2 NVMe SSD slot, we also expect to see Thunderbolt 3 ports and a more powerful Wi-Fi solution for the flagship configuration in future iterations.