Silicon Power's flash storage product line caters extensively to the entry-level market. In October 2023, the company introduced two new portable SSDs in a thumb drive form-factor. The MS70, with a single USB 3.2 Gen 2 Type-A interface, is now available in capacities ranging from 250GB to 2TB. The DS72 (also available in the same capacities) has a dual-interface design with both Type-C and Type-A interfaces. Performance claims of 1050 MBps reads and 850 MBps writes land the MS70 and DS72 in the high-capacity high-performance UFD segment.

The company has traditionally relied on introducing products into well-established market segments, with specifications that do not typically make them stand out. However, the two new products caught our attention, as they happen to be one of the first reasonably-priced 2TB thumb drives in the retail market.

The high-performance USB flash drive (UFD / thumb drive) segment has been steadily gaining more entrants since the introduction of Kingston's DataTraveler Max in late 2021. Transcend's ESD300 and ESD310, along with Silicon Power's MS70 and DS72 are making an attempt to differential themselves from the rest of the pack by offering 2TB SKUs. This review takes a detailed look at the performance and value proposition of the 2TB version of the Silicon Power MS70.

Introduction and Product Impressions

USB flash drives have grown both in storage capacity and speeds over the last few years. Thanks to the advent of 3D NAND and rapid iterations with performance improvements in the USB specifications, we are now seeing SSD-in-a-stick products capable of delivering 1GBps+ speeds.

The thumb drive form factor is attractive for multiple reasons - there is no separate cable to carry around, and the units are usually light and compact. High-performance thumb drives based on SSD platforms were introduced in the mid-2010s, but the thermal solution and size made them unwieldy. The category was made viable only after the introduction of high-performance native UFD controllers from Phison and Silicon Motion. We have already reviewed multiple PSSDs based on these two controllers, including the Transcend ESD310C and the OWC Envoy Pro Mini in the thumb drive category.

The new Silicon Power MS70 aims to differentiate itself from other high-performance thumb drives based on two aspects - available capacity points, and compact case design. Despite its thumb drive form-factor, the MS70 takes full advantage of its USB 3.2 Gen 2 Type-A connector by promising speeds of up to 1050 MBps. The company sampled us the 2TB version to put through our direct-attached storage test suite.

The thumb drive is the only component in the package, and all of the usage and warranty information is printed on the back. Our sample came from an early batch, as the same SKU currently being sold also includes a Type-A to Type-C adapter.

There are no value-additions like lanyards or bundled software, but that is reflected in the aggressive pricing strategy adopted by Silicon Power - around 5¢ per GB for the highest capacity SKU. In any case, the target market for these thumb drives is unlikely to be enticed by backup software or hardware encryption-supporting password applications.

The casing is made of rubber and aluminum, with the former in place around the edges and the connector's protective cap. The product has a sturdy feel to it, unlike the relatively flimsy construction of the Transcend ESD310C. The MS70 is slightly larger, but the dimensions are still small enough to avoid problems with port blocking.

There was no obvious way to tear down the sample for the purpose of determining the controller and the flash being used. However, CrystalDiskInfo provides a quick overview of the capabilities of the storage device. A look at the firmware version (UHFM00.6) and a cursory online search revealed that the Silicon Power MS70 is powered by the Phison U17 controller. Silicon Power confirmed the use of SK hynix 3D TLC NAND in our sample, but did mention that they reserved the right to use any NAND with similar performance in future production runs.

Prior to looking at the benchmark numbers, power consumption, and thermal solution effectiveness, a description of the testbed setup and evaluation methodology is provided.

Testbed Setup and Evaluation Methodology

Direct-attached storage devices (including thumb drives) are evaluated using the Quartz Canyon NUC (essentially, the Xeon / ECC version of the Ghost Canyon NUC) configured with 2x 16GB DDR4-2667 ECC SODIMMs and a PCIe 3.0 x4 NVMe SSD - the IM2P33E8 1TB from ADATA.

The most attractive aspect of the Quartz Canyon NUC is the presence of two PCIe slots (electrically, x16 and x4) for add-in cards. In the absence of a discrete GPU - for which there is no need in a DAS testbed - both slots are available. In fact, we also added a spare SanDisk Extreme PRO M.2 NVMe SSD to the CPU direct-attached M.2 22110 slot in the baseboard in order to avoid DMI bottlenecks when evaluating Thunderbolt 3 devices. This still allows for two add-in cards operating at x8 (x16 electrical) and x4 (x4 electrical). Since the Quartz Canyon NUC doesn't have a native USB 3.2 Gen 2x2 port, Silverstone's SST-ECU06 add-in card was installed in the x4 slot. All non-Thunderbolt devices are tested using the Type-C port enabled by the SST-ECU06.

The specifications of the testbed are summarized in the table below:

The testbed hardware is only one segment of the evaluation. Over the last few years, the typical direct-attached storage workloads for memory cards have also evolved. High bit-rate 4K videos at 60fps have become quite common, and 8K videos are starting to make an appearance. Game install sizes have also grown steadily even in portable game consoles, thanks to high resolution textures and artwork. Keeping these in mind, our evaluation scheme for portable SSDs and UFDs involves multiple workloads which are described in detail in the corresponding sections.

• Synthetic workloads using CrystalDiskMark and ATTO
• Real-world access traces using PCMark 10's storage benchmark
• Custom robocopy workloads reflective of typical DAS usage
• Sequential write stress test

In the next section, we have an overview of the performance of the Silicon Power MS70 in these benchmarks. Prior to providing concluding remarks, we have some observations on the UFD's power consumption numbers and thermal solution also.

Benchmarks such as ATTO and CrystalDiskMark help provide a quick look at the performance of the direct-attached storage device. The results translate to the instantaneous performance numbers that consumers can expect for specific workloads, but do not account for changes in behavior when the unit is subject to long-term conditioning and/or thermal throttling. Yet another use of these synthetic benchmarks is the ability to gather information regarding support for specific storage device features that affect performance.

Synthetic Benchmarks - ATTO and CrystalDiskMark

Silicon Power claims read and write speeds of 1050 MBps and 850 MBps respectively. Based on the ATTO benchmarks below, it appears that Silicon Power has been a bit conservative in its write speed claims. ATTO benchmarking is restricted to a single configuration in terms of queue depth, and is only representative of a small sub-set of real-world workloads. It does allow the visualization of change in transfer rates as the I/O size changes, with optimal performance being reached around 1 MB for a queue depth of 4.

Full System Drive Benchmark Bandwidth (MBps)Full System Drive Benchmark Latency (us)Full System Drive Benchmark ScoreExpand All

Based on the results observed in various individual traces, it comes as no surprise to see the MS70 placed second from last in the overall metrics. Only the Files Transfers workload component bears relevance to Silicon Power's focus with the MS70, and the numbers in that don't contribute enough to prevent it from dropping to the bottom half of the pack.

The performance of different high-performance UFDs in various real-world access traces as well as synthetic workloads was brought out in the preceding sections. We also looked at the performance consistency for these cases. Power users may also be interested in performance consistency under worst-case conditions, as well as drive power consumption. The latter is also important when used with battery powered devices such as notebooks and smartphones. Pricing is also an important aspect. We analyze each of these in detail below.

Worst-Case Performance Consistency

Flash-based storage devices tend to slow down in unpredictable ways when subject to a large number of small-sized random writes. Many benchmarks use that scheme to pre-condition devices prior to the actual testing in order to get a worst-case representative number. Fortunately, such workloads are uncommon for direct-attached storage devices, where workloads are largely sequential in nature. Use of SLC caching as well as firmware caps to prevent overheating may cause drop in write speeds when a flash-based DAS device is subject to sustained sequential writes.

Our Sequential Writes Performance Consistency Test configures the device as a raw physical disk (after deleting configured volumes). A fio workload is set up to write sequential data to the raw drive with a block size of 128K and iodepth of 32 to cover 90% of the drive capacity. The internal temperature is recorded at either end of the workload, while the instantaneous write data rate and cumulative total write data amount are recorded at 1-second intervals.

CrystalDiskMark Workloads - Power Consumption
TOP: Silicon Power MS70 2TBOWC Envoy Pro Mini 1TBTranscend ESD310C 1TBKingston DT Max 1TBKingston DTMAXA/1TB	BOTTOM: OWC Envoy Pro Mini 1TBTranscend ESD310C 1TBKingston DT Max 1TBKingston DTMAXA/1TBSilicon Power MS70 2TB

The MS70 has a peak power consumption of 2.97W, though it sips less than 2W during most of the workload processing. Except for the peak numbers, the power consumption profile of the OWC Envoy Pro Mini and the Silicon Power MS70 look remarkably similar, down to the time taken for entry into a deep-sleep state.

Final Words

The Silicon Power MS70 was introduced into the market just last month, and is yet to become widely available. Currently, the drive is available for purchase only in Silicon Power's own storefront. The SKUs are priced at $20 for the 250GB version ($38 outside the year-end promotion period), and $30 for the 500GB one ($46 outside the promotion period), The 1TB and 2TB versions are priced at $63 and $101 respectively. These are very aggressive price points, even better than the 7.5¢ / GB of the Transcend ESD310C we were recommending last month.

Based on the evaluation of different UFDs (thumb drives) based on controllers from both Silicon Motion and Phison, it is clear that the former excels at application workloads, while delivering passable numbers for file transfers. Phison drives are optimized for file transfer workloads, but the delta for regular application access traces is a bit higher than Silicon Motion's delta for the other use case. Silicon Power has attempted to address this by incorporating a large amount of SK hynix 3D TLC NAND flash. That helps the MS70 in providing better overall performance compared to the Silicon Motion units employing the relatively old BiCS 5 NAND from Kioxia.

7TB+ writes, and 4TB+ reads at the end of our testing routine

At around $100 for a 2TB thumb drive, it is easy to look past the minor performance flaws of the MS70. The absolute performance numbers were not great, but the unit was remarkably consistent in delivering them across repeated stress testing. In terms of value proposition, the product comes out on top by a huge margin.