Back at Intel's Innovation 2022 event in September, the company let it be known that it had plans to release a '6 GHz' processor based on its Raptor Lake-S series of processors. Though it didn't come with the same degree of fanfare that Intel's more imminently launching 13900K/13700K/13600K received, it put enthusiasts and industry watchers on notice that Intel still had one more, even faster Raptor Lake desktop chip waiting in the wings.

Now a few months later, Raptor Lake's shining moment has arrived. Intel has launched the Intel Core i9-13900KS, a 24-core (8x Perf + 16x Efficiency) part with turbo clock speeds of up to 6 GHz. A mark, which until very recently, was unprecedented without the use of exotic cooling methods such as liquid nitrogen (LN2). 

In what is likely to be one of the last in a wide range of Raptor Lake-S SKUs to be announced, Intel has seemingly saved its best for last. The Intel Core i9-13900KS is the faster and unequivocal bigger brother to the Core i9-13900K, with turbo clock speeds of up to 6 GHz while maintaining its halo presence with a 200 MHz increase on both P-core and E-core base frequencies.

Intel's focus and strategy on delivering halo-level processors in limited supply is something that's become a regular part of their product stack over the last few years. We've previously seen the Core i9-9900KS (Coffee Lake) and i9-12900KS (Alder Lake), which were relative successes in showcasing each Core architecture at their finest point. The Core i9-13900KS looks to follow this trend, although it comes as we've reached a time where power efficiency and costs are just a few widely shared concerns globally.

Having the best of the best is somewhat advantageous when there's a need for cutting-edge desktop performance, but at what cost? Faster cores require more energy, and more energy generates more heat; 6 GHz for the average consumer is finally here, but is it worth taking the plunge? We aim to find out in our review of the 6 GHz Core i9-13900KS.

The Intel Core i9-13900KS: Raptor Lake Goes to 6 GHz

AMD and Intel's R&D teams have been working hard in the last few years to keep trading blows in key areas such as core count, IPC performance, and, of course, price. When it comes to focusing on what flagship CPUs are, some gain their status by offering large numbers of cores and very respectable clock speeds to gain that edge in performance over the competition. While getting the right balance of more cores with faster speeds is advantageous, Intel and AMD have in recent years definitely pushed their silicon to very near their ability and capability limits.

The Intel Core i9-13900KS is a juxtaposition in combining high core count with incredibly high frequencies into one silicon package that can be slotted into an appropriate LGA1700 motherboard. It still has the same 24 CPU cores that the Core i9-13900K has. Concerning specifications, all are the same except for clock speeds and TDP. The Core i9-13900KS has eight Raptor Cove Performance (P) cores for the compute workloads potatoes, while sixteen are Efficiency (E) cores based on the Gracemont architecture to pick up other areas of slack.

Intel's hybrid architecture design of performance and efficiency cores, sometimes called big/little, works well. However, it does require a suitable operating system (these days, Windows 11) to utilize the Thread Director scheduling efficiently and effectively.

Intel 13th Gen Core i9 Series (Raptor Lake-S)
AnandTech	Cores P+E/T	P-Core Base	P-Core Turbo	E-Core Base	E-Core Turbo	L3 Cache (MB)	IGP	Base W	Turbo W	Price ($)
i9-13900KS	8+16/32	3200	6000	2400	4300	36	770	253	253/320	$699
i9-13900K	8+16/32	3000	5800	2200	4300	36	770	125	253	$589
i9-13900KF	8+16/32	3300	5800	2200	4300	36	-	125	253	$564
i9-13900	8+16/32	2000	5600	1500	4200	36	770	65	219	$549
i9-13900F	8+16/32	2000	5600	1500	4200	36	-	65	219	$524
i9-13900T	8+16/32	1100	5300	800	3900	36	770	35	106	$549

What makes the Core i9-13900KS different from the rest of the 13th Gen Core i9 series line-up, aside from the apparent increases in P-core and E-core base frequencies and a 6 GHz turbo, is that is a special bin from existing silicon. Experiences with the Core i9-13900K in terms of overclocking ability are mixed, with few of these chips having the capability to run at 6 GHz without exotic cooling methods such as liquid nitrogen and dry ice.  

While matching batch numbers is usually the closest method to obtaining parity levels in overclocking ability, it's not an exact science. Talking realistically, no two processors are the same when they come out of the factory. The benefit of having Intel bin their silicon in-house for its KS series is helpful for extreme overclockers, as its guarantees that each i9-13900KS will hit turbo clock speeds of 6 GHz; on two of the P-cores, at least. This also means the Core i9-13900KS, by default, will draw more power and run hotter – upwards of 320 Watts, to be precise.

Looking at the specifications of the Core i9-13900KS, it has 24 cores (8P+16E) and 32 threads, with a maximum P-core turbo of up to 6 GHz. This makes it the fastest desktop processor on the market today, considering out-of-the-box settings and automated technologies implemented. Intel has also increased P-core and E-core base frequencies by 200 MHz from the regular 13900K, making the P-core base on the 13900KS 3.2 GHz and the E-core base 2.4 GHz. All of Intel's 13th Core Series SKUs support either DDR5-5600 or DDR4-3200 memory, which benefits users on a budget. However, buyers of the Core i9 series are likely to opt for DDR5 memory due to extra levels of performance.

The Core i9-13900KS hit 6 GHz on cores P4 and P5 during the XTU stress test (albeit with thermal throttling)

Intel has also increased the base TDP from 125 W to 150 W to account for the additional bump to P and E-core frequencies. What's interesting is that Intel has provided a maximum turbo power specification of 253 W. The other value Intel provides is its new Extreme Power Delivery (EPD) profile of 320 W. This makes it one of the most power-hungry processors out of the box, especially when at full-load in a compute-heavy task.

Attaining 6 GHz

Outside of the 6 GHz capabilities that the Core i9-13900KS has and the increases mentioned above in base frequencies and power nuances, it shares identical specifications to the Core i9-13900K. This includes the same 36 MB of shared L3 cache across the board, 2 MB of L2 cache per performance (P) core, with 4 MB of L2 cache per each quad efficiency (E) core cluster.

The Intel Core i9-13900KS retail packaging

Things to Know Before Interpreting Our Test Results: Extreme Delivery Profile is 320 W (PL1/PL2)

Expanding into Intel's new Extreme Delivery Profile enables higher power limits on the Core i9-13900KS. As per Turbo Boost Max 3.0, this is set to 253 W, the same PL1/PL2 value as on the Core i9-13900K. For the Core i9-13900KS, the Extreme Delivery Profile enables a higher profile, increasing to 320 W for the PL1 and PL2 values. This allows the Core i9-13900KS more power headroom to enable higher frequencies on two cores, which for Turbo Boost Max 3.0 is 5.8 GHz, and Thermal Velocity Boost is 6.0 GHz. 

Intel Core i9-13900KS P-Core Turbo Frequencies (With Thermal Velocity Boost Active)
AnandTech	1 Core	2 Cores	3 Cores	4 Cores	5 Cores	6 Cores	7 Cores	8 Cores
Max Frequency (GHz)	6.0	6.0	5.6	5.6	5.6	5.6	5.6	5.6

This completely disregards Intel's base TDP of 150 W, which by default, is also moot on the regular Core i9-13900K as this chip also employs an Extreme Delivery Profile of 253 W for the PL1 and PL2 values. Of course, it has to be stated that motherboard vendors typically ignore PL1 and PL2 values through their implementation of Multi-Core Enhancement (MCE), and they typically go for broke.

Regarding expected performance levels, this is likely to come down to one key area; heat dissipation. The extra heat from the frequency hikes will require more aggressive cooling, and as we saw from our review of the Core i9-12900KS, the KS chips not only run with lots more power compared to the K-series counterparts, but they aren't the easiest to keep cool either.

One thing that is important to consider is that the motherboard has to have a solid power delivery capable of sustaining up to 400 A (ICCMax) to allow the Core i9-13900KS. While the Core i9-13900KS will work in any Z690 and Z790 motherboard, it doesn't mean it should be used just because it works. Look for a motherboard with a decent quality power delivery and good VRM thermal capabilities before considering this chip to operate optimally.

While the premise of the KS series is very favorable for some, it does require more than just installing it into a motherboard and any cooler to get optimal performance. Even with premium AIO coolers, users are likely to expect at least some thermal throttling on the KS chips - 253mm² is simply not a lot of surface area to be dissipating 320 Watts, even with the help of a heat spreader. The best-case scenario would be a reasonable and well-thought-out custom water cooling loop with premium components and competent cooling fans. This not only adds a very hefty outlay to the cost, but achieving the best performance levels has never been a cheap process to aim for.

The Current CPU Test Suite

For our Intel Core i9-13900KS testing, we are using the following test system:

Intel 13th Gen Core System (DDR5)
CPU	Core i9-13900K ($589) 24 Cores, 32 Threads 125 W TDP Core i5-13600K ($319) 14 Cores, 20 Threads 125 W TDP
Motherboard	GIGABYTE Z690 Aorus Master*
Memory	SK Hynix 2x16 GB DDR5-5600B CL46
Cooling	EKWB EK-AIO Elite 360 D-RGB 360mm
Storage	SK Hynix Platinum P41 2TB PCIe 4.0 x4
Power Supply	Corsair HX1000
GPUs	AMD Radeon RX 6950 XT, 31.0.12019
Operating Systems	Windows 11 22H2

*We changed the motherboard to the GIGABYTE Z690 Aorus Master as the MSI MPG Z790 Carbon WIFI we used for our previous 13th Gen Core series reviews refused to play ball. We don't like to make these changes lightly, but we weren't able to source another Carbon in time for this review

It should be noted that there are no CPU performance differences between Z690 and Z790 motherboards; just that the newer Z790 models benefit from more I/O options. This was confirmed to us by Intel before the release of the 13th Gen Core series.

Our updated CPU suite for 2023 includes various benchmarks, tests, and workloads designed to show variance in performance between different processors and architectures. These include UL's latest Procyon suite with both office and photo editing workloads simulated to measure performance in these tasks, CineBench R23, Dwarf Fortress, Blender 3.3, and C-Ray 1.1.  

Meanwhile, we've also carried over some older (but still relevant/enlightening) benchmarks from our CPU 2021 suite. This includes benchmarks such as Dwarf Fortress, Factorio, and Dr. Ian Cutress's 3DPMv2 benchmark.

We have also updated our pool of games going forward into 2023 and beyond, including the latest F1 2022 racing game, the CPU-intensive RTS Total War: Warhammer 3, and the popular Hitman 3.

Due to various issues with Cyberpunk 2077 giving us odd results, we've omitted this from future testing until we can identify the issue and apply a fix.

CPU Benchmark Performance: Power And Office

Our previous sets of ‘office’ benchmarks have often been a mix of science and synthetics, so this time we wanted to keep our office section purely on real-world performance. We've also incorporated our power testing into this section too.

The biggest update to our Office-focused tests for 2023 and beyond include UL's Procyon software, which is the successor to PCMark. Procyon benchmarks office performance using Microsoft Office applications, as well as Adobe's Photoshop/Lightroom photo editing software, and Adobe Premier Pro's video editing capabilities. Due to issues with UL Procyon and the video editing test, we haven't been able to properly run these, but once we identify a fix with UL, we will re-test each chip.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Clockspeeds

Taking a quick look at clockspeeds, we know that the i9-13900KS can hit 6.0GHz on just two of its CPU cores – the so called "favored cores" under Turbo Boost Max 3.0 (TBM3). This is a combination of TBM3 allowing these best cores to get to 5.8GHz, and then TVB taking them to 6.0GHz when there's suitable thermal headroom.

Once you exceed 2 threads (or rather, needing to occupy 2 CPU cores), however, then i9-13900KS has to back off on its clockspeeds, even under the most opportunistic scenarios. In this case the highest clockspeed available, regardless of which cores are in use, is 5.6GHz, the set limit for Intel's Adaptive Boost Technology (ABT). Long and short, this means that in workloads with more than a couple of threads (e.g. encoding and most games), the highest the chip is going to be able to clock is 5.6GHz.

*both P-Core 4 and 5 are designated for Turbo Boost Max 3.0 and Thermal Velocity Boost (TVB)

Overall from our 5-minute test looping CineBench's Multi-Threaded test, the above table illustrates each P-Core maximum frequency, along with the average frequency for the run duration. The designated cores for Intel's TBM3 on this particular Core i9-13900KS sample were P-Core 4 and P-Core 5. Both of these cores hit 6 GHz as advertised, but due to TBM3 limitations in this MT test, they didn't remain at 6 GHz for long, as we can see. The average frequency is the important one, as this is the typical core clock speed on each of the P-Cores for our 5-minute blast.

Power

The nature of reporting processor power consumption has become, in part, a bit of a nightmare. Historically the peak power consumption of a processor, as purchased, is given by its Thermal Design Power (TDP, or PL1). For many markets, such as embedded processors, that value of TDP still signifies the peak power consumption. For the processors we test at AnandTech, either desktop, notebook, or enterprise, this is not always the case.

Modern high-performance processors implement a feature called Turbo. This allows, usually for a limited time, a processor to go beyond its rated frequency. Exactly how far the processor goes depends on a few factors, such as the Turbo Power Limit (PL2), whether the peak frequency is hard coded, the thermals, and the power delivery. Turbo can sometimes be very aggressive, allowing power values 2.5x above the rated TDP. And in the case of high-performance processors on high-end motherboards, all of these values are arguably theoretical anyhow, as motherboard vendors will commonly throw the limits out the window and let chips draw all the power they want in order to wring out every last bit of performance.

AMD and Intel have different definitions for TDP that are, broadly speaking, applied the same. The difference comes from turbo modes, turbo limits, turbo budgets, and how the processors manage that power balance. These topics are 10000-12000 word articles in their own right, and we’ve got a few articles worth reading on the topic.

• Why Intel Processors Draw More Power Than Expected: TDP and Turbo Explained
• Talking TDP, Turbo and Overclocking: An Interview with Intel Fellow Guy Therien
• Reaching for Turbo: Aligning Perception with AMD’s Frequency Metrics
• Intel’s TDP Shenanigans Hurts Everyone

The peak power figures from our power testing show that the Core i9-13900K drew an impressive 359.9 W at full load. This puts it around 26 W higher than our testing in our review of the Core i9-13900K, which given the bumps to the P-core and E-core base frequencies, along with the 6 GHz turbo clock speed on the P-cores, isn't that bad.

Of course, a processor pulling 360 W in an age where home energy prices are at record highs globally isn't very favorable for various reasons. There's not much efficiency from the Intel 7 process at these levels, especially when directly compared to the 5 nm AMD Zen 4 core. The other caveat is 360 W isn't that easy to cool in a conventional desktop case with a typical tower air cooler, and users looking to use the Core i9-13900KS (and 13900K) need to invest in a suitable premium AIO cooler or custom water cooling for optimal performance.

Moving deeper into our Core i9-13900KS Prime 95 sustained power test, we can see that the chip is consistently hitting between 330 W and 340 W for a prolonged period. At the beginning of the workload being placed on the cores, it hits 359.9 W very quickly through the 6 GHz cores amid the extra power requirements this needs to work optimally.

While we saw a much more sporadic sustained power draw on the Core i9-13900K, the Core i9-13900KS draws more power for a longer period. The 6 GHz P-core turbo quickly started to drop off, and within half a minute, the power was down from 360 W to around 340 W before settling somewhat.

Office/Web

In our office and web-based benchmarks, the Core i9-13900KS, for the most part, was marginally better than the Core i9-13900K. This is expected, although we saw a significant performance jump in UL's Procyon Microsoft Office Outlook test.

CPU Benchmark Performance: Science

Our Science section covers all the tests that typically resemble more scientific-based workloads and instruction sets. For our 2023 CPU suite, we've also added SciMark 2.0 which measures numerical kernels and various computational routines found in numeric coding.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Science

Our science-focused benchmarks highlight the fact the Core i9-13900KS and Core i9-13900K are both very similar in regard to performance. Outside of the 3DPM v2.1 AVX test where AMD gains the advantage in actually supporting AVX-512 instruction sets, the additional bump to base and turbo clock speeds doesn't yield too much benefit here.

CPU Benchmark Performance: Simulation

Simulation and Science have a lot of overlap in the benchmarking world. The benchmarks that fall under Science have a distinct use for the data they output – in our Simulation section, these act more like synthetics but at some level are still trying to simulate a given environment.

In the encrypt/decrypt scenario, how data is transferred and by what mechanism is pertinent to on-the-fly encryption of sensitive data - a process by which more modern devices are leaning to for software security.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Simulation

Focusing on our simulation-based testing, once again the Core i9-13900KS and Core i9-13900K are very close in terms of performance. 

CPU Benchmark Performance: Rendering And Encoding

Rendering tests, compared to others, are often a little more simple to digest and automate. All the tests put out some sort of score or time, usually in an obtainable way that makes it fairly easy to extract. These tests are some of the most strenuous in our list, due to the highly threaded nature of rendering and ray-tracing, and can draw a lot of power.

If a system is not properly configured to deal with the thermal requirements of the processor, the rendering benchmarks are where it would show most easily as the frequency drops over a sustained period of time. Most benchmarks in this case are re-run several times, and the key to this is having an appropriate idle/wait time between benchmarks to allow for temperatures to normalize from the last test.

One of the interesting elements of modern processors is encoding performance. This covers two main areas: encryption/decryption for secure data transfer, and video transcoding from one video format to another.

In the encrypt/decrypt scenario, how data is transferred and by what mechanism is pertinent to on-the-fly encryption of sensitive data - a process by which more modern devices are leaning to for software security.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Rendering

Both the Core i9-13900KS and Core i9-13900K trade blows regarding rendering performance. In some instances, such as POV-Ray, it seems that the slight thermal throttling of the 13900KS did hinder things here a little, but in Cinebench R23, the Core i9-13900KS shone in the single-threaded test.

Encoding

When it comes to encoding, the Core i9-13900KS takes away as many wins as it does losses against the Core i9-13900K. The Core i9-13900KS does take a big win in our WinRar 5.90 benchmark by a solid 3.3 seconds.

CPU Benchmark Performance: Legacy Tests

In order to gather data to compare with older benchmarks, we are still keeping a number of tests under our ‘legacy’ section. This includes all the former major versions of CineBench (R15, R11.5, R10) as well as Geekbench 4 and 5. We won’t be transferring the data over from the old testing into Bench, otherwise, it would be populated with 200 CPUs with only one data point, so it will fill up as we test more CPUs like the others.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Legacy

Even though the majority of our legacy tests are aged, the Core i9-13900KS takes the performance crown in most of them. The most notable of these wins are in single-threaded tests such as the older CineBench benchmarks, while multi-threaded performance in Geekbench 5 is also indicative of the extra clock speed on offer.

Gaming Performance: iGPU

Despite updating the main bulk of our CPU test suite for 2023 and beyond, we've not had a chance to test every integrated graphics chip in our stack of CPUs. As a result of this, we've included limited results for our iGPU-based gaming tests, although it is more than enough to get to grips with improvements in Raptor Lake performance.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Final Fantasy 14

World of Tanks

Borderlands 3

Far Cry 5

Grand Theft Auto V

Strange Brigade (DirectX 12)

The Intel Core 13th and 12th Gen Core series processors use Intel's Xe-LP based 770 UHD graphics processor. This means that graphical performance is very similar between both families.

With faster cores at both base and turbo frequencies, the Core i9-13900KS has a slight advantage over the Core i9-13900K series chip. However, it is very unlikely users will opt for a halo CPU such as this to be doing anything with the integrated graphics.

Gaming Performance: 720p And Lower

The reason we test games in CPU reviews at lower resolutions such as 720p and below is simple; titles are more likely to be CPU bound than they are GPU bound at lower resolutions. This means there are more frames for the processor to process as opposed to the graphics card doing the majority of the heavy lifting.

There are some variances where some games will still use graphical power, but not as much CPU grunt at these smaller resolutions, and this is where we can show where CPU limitations lie in terms of gaming.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Civilization VI

World of Tanks

Borderlands 3

Grand Theft Auto V

Red Dead Redemption 2

F1 2022

Hitman 3

Total War: Warhammer 3

When it comes to raw processor performance in gaming, lower resolutions showcase the ability best of all. In the case of the Core i9-13900KS and Core i9-13900K, both processes, as expected, are very competitive against each other. Sometimes, the higher-clocked KS SKU comes out on top, and sometimes it doesn't.

There can be some weight put on the fact in some cases, the Core i9-13900KS hits thermal limits much more easily, even with a premium 360mm CLC cooler that we are using. In World of Tanks at 768p, the Core i9-13900KS bridges the gap to the fast yet older Core i9-12900KS, which seems to benefit from a mixture of IPC, core frequency, and core count. 

Looking at our Borderlands 3 results at 360p, the Core i9-13900KS plows through the test with flying colors, although the AMD Ryzen 7 5800X3D and its 96 MB of 3D V-Cache make it competitive. This is relevant as AMD plans to release the updated Ryzen 7000 X3D SKUs very soon.

Gaming Performance: 1080p

Moving along, here's a look at a more balanced gaming scenario, running games at 1080p with maximum image quality.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Civilization VI

World of Tanks

Borderlands 3

Grand Theft Auto V

Red Dead Redemption 2

F1 2022

Hitman 3

Total War: Warhammer 3

Even though gamers find 1440p and 4K resolutions more to their liking, the 1920 x 1080p resolution is still more widely used than expected (even in 2023). Across all of our games tested at 1080p, the Core i9-13900KS and Core i9-13900K compete heavily against each other. In some cases, the extra frequency of the Core i9-13900KS helps, especially in compute-heavy games such as Civilization VI and Hitman 3.

In graphically intensive games (where GPU power exceeds the requirement for compute), both remain competitive with other recent chips on the market from their selection of 13th Gen Core series SKUs and AMD's Ryzen 7000 family.

Gaming Performance: 1440p

In our Ryzen 7000 series review, we saw users commenting about testing games for CPU reviews at 1440p, so we have duly obliged here. Those interested in 1440p performance with minimal image quality – particularly the esports crowd – will be glad to know that we will be testing at this resolution going forward into 2023 and beyond.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Civilization VI

Borderlands 3

Grand Theft Auto V

Red Dead Redemption 2

F1 2022

Hitman 3

Total War: Warhammer 3

At 2560 x 1440p resolutions, things start to become a bit more graphics limited than compute. This means the performance of the Core i9-13900KS and Core i9-13900K processors aren't much different.

What our testing essentially shows is that when paired with an AMD Radeon RX 6950 XT graphics card, the 6 GHz turbo clock speed on the Core i9-13900KS makes virtually no difference at 1440p when compared to the Core i9-13900K.

Gaming Performance: 4K

Last, we have our 4K gaming results.

We are using DDR5 memory on the 12th and 13th Gen Core parts, as well as the Ryzen 7000 series, at the following settings:

• DDR5-5600B CL46 - Intel 13th Gen
• DDR5-5200 CL44 - Ryzen 7000
• DDR5-4800 (B) CL40 - Intel 12th Gen

All other CPUs such as Ryzen 5000 and 3000 were tested at the relevant JEDEC settings as per the processor's individual memory support with DDR4.

Civilization VI

World of Tanks

Borderlands 3

Grand Theft Auto V

Red Dead Redemption 2

F1 2022

Hitman 3

Total War: Warhammer 3

At 4K resolutions (3840 x 2160), things become more interesting, albeit with the Core i9-13900KS and Core i9-13900K remaining highly competitive; for the most part. While things are mainly GPU limited at these high resolutions, there's still some breathing space in certain titles that will benefit from better IPC, core count, and frequency.

In Civilization VI at 4K, the Core i9-13900KS performs better than the regular K-series SKU in both average and 95th percentile frame rates. At the same time, the same can be said about the marginal gains in Borderlands 3 and Grand Theft Auto V. In the other games tested, things are hit and miss, with the Core i9-13900K winning some and the Core i9-13900KS winning others.

Conclusion

As we first found out when we reviewed the Intel Core i9-13900K and Core i5-13600K processors, Intel's Raptor Lake has proved to be a proverbial performance powerhouse compared to the previous Alder Lake (12th Gen) architecture. Intel managed to not only improve a bit upon single-threaded IPC performance while boosting clockspeeds for single-threaded performance, but the company also doubled the number of Efficiency (E) cores to give its silicon more grunt in multi-threaded workloads. 

Regarding the upper echelon of desktop processors, Intel and AMD trade blows in many aspects, not just in gaming and compute performance but also in price. As we've seen from Intel recently, at least with the 9th Gen and 12th Gen Core families, it likes to save its best silicon for last: the KS special edition SKU with the highest clockspeeds they can reasonably attain.

One slice of wafer or two? Core i9-13900KS inner packaging

Talking about its 12th Gen (Alder Lake) in particular, the launch of the Core i9-12900KS came around when AMD launched its X3D SKU, the Ryzen 7 5800X3D with 3D V-Cache packaging technology in a bid to counteract its favorability in gaming performance. The same could theoretically be said about the 6 GHz-laden Core i9-13900KS, as AMD's updated 7000 series X3D SKUs are expected very soon, and the launch dates seem to be aligned to counteract AMD once again. For reference, the Core i9-13900KS was officially launched on retail shelves earlier this month on the 12th Jan. AMD's Ryzen 7000 X3D series chips are due sometime in February.

So onto the meat and potatoes of our Core i9-13900KS review, the analysis. With ample time to test and learn specific characteristics of Intel's ultra-fast Core i9 13900KS processor, it has been a bit of a mixed bag. It was always going to be a chip of extremes thanks to clock speeds of 6 GHz, and upon first hearing about Intel's announcement to launch a 6 GHz SKU, my initial thought was shared by many; how is it going to be tamed when Intel's previous KS chips have notoriously been so hungry when it comes to power and temperatures?

Intel Core i9-13900KS Performance Analysis

Opening up our analysis with a little bit of background, Intel's Core i9-13900K (24-core 8P+16E) and AMD's Ryzen 9 7950X (16-core) are remarkably like a battle between cat and mouse; both chips are high quality, possess oodles of performance, and compete very closely when pushed to the limit. 

Add the Core i9-13900KS to the mix, and it starts to tilt the deck to Intel's favor with its 6 GHz P-Core turbo clock speeds, higher all P-Core turbo, and higher P-core and E-core base frequencies. How much it improves on existing CPUs depends on the workload, the task, and the situation you put it in.

In our WinRAR 5.90 benchmark, the increased frequencies on the Core i9-13900KS yielded some good gains in performance, with a 3.3-second quicker encoding time compared to the Core i9-13900K. Comparing it to the AMD Ryzen 9 7950X, it encoded our 3477 files (1.96 GB) quicker by around 4.6 seconds. There are slight benefits to single-threaded performance through the higher P-core turbo clock speeds, but not enough to justify the additional cost in our testing, at least not from an apples-to-apples comparison.

From the rest of our benchmarks from our updated 2023 CPU suite, there wasn't much else to write home about for the Core i9-13900KS, as we saw marginal gains in rendering, encoding, simulation, and scientific-based workloads when compared to the 13900K; both competed very closely with each other throughout. The greatest gains from the 13900KS are going to be in lightly-threaded workloads where it can flex its muscles and properly hit 6.0GHz on up to 2 cores; so large, multi-threaded workloads don't benefit by quite as much.

That will most likely not be the summarization that users want to hear, but that's only half of the story, which I'll elaborate on further in our analysis. 

Touching a little on gaming performance, and as we expected to see, there wasn't much difference in our testing between the Core i9-13900KS and Core i9-13900K to pick a genuinely decisive winner. The 6 GHz Core i9-13900KS would come out on top in some games (marginally), and the Core i9-13900K would keep ahead. Perhaps the most interesting element from our games testing with our AMD Radeon RX 6950 XT graphics card was that in situations where the AMD Ryzen 7950X was ahead, the Core i9-13900KS didn't bridge the gap with its higher clocked cores.

Core i9-13900KS: 6 GHz, Power, and Thermal Analysis

As Intel is proud, and rightly so, of achieving a retail processor with clock speeds of 6 GHz out of the box, this isn't the entire story, and different narratives depend on requirements and how they are looked upon. The Core i9-13900KS is a 6 GHz processor, and from our testing, we have seen two of the eight P-Cores hit 6 GHz, so it must be a 6 GHz processor, right? Well, this is where things become interesting.

Click on the chart to enlarge

Looking at the core frequency data from a CineBench R23 Multi-Threaded test running on a loop for 5 minutes, we can see how the two defined 6 GHz boost P-cores behave. The two designated cores did indeed hit 6 GHz pretty much instantaneously, but within a couple of seconds of this, the heat became too much, and they quickly dropped to between 5.4 and 5.6 GHz along with the rest of the P-Cores.

The frequency constraints are down to thermal throttling, as Intel is using its Thermal Velocity Boost (TVB) to go from 5.8 to 6 GHz, but from our testing, this isn't sustained with the heavy thermal overhead required to keep things cool.

Click the chart to enlarge

From the same CineBench R23 MT 5-minute loop test we ran, we can see the effect on both power and thermals. The Core i9-13900KS peaked at 360.2 W in power at its highest point around 18 seconds into the run, while die temperatures regularly hit the 100°C mark, which meant that thermal throttling was inevitable from the get-go; it only took 12-seconds for heat to become an issue, even with our premium EKWB 360 mm AIO CPU cooler. And from talking with other hardware reviewers, it's clear that we're not alone in seeing this.

The other interesting element is Intel's binning process, which should yield users with better silicon to overclock with compared to the Core i9-13900K. Xaver Amberger from IgorsLab has recently published some binning data from a wide selection of Core i9-13900K, Core i9-13900KF, and Core i9-13900KS samples with an ASUS ROG Maximus Z790 Hero motherboard using its SP value; a measure of determining how good the chip is for overclocking.

The consensus from their testing ties in with our thoughts that the Core i9-13900KS has a variably higher level of binning, thus giving users a higher chance of getting better silicon than opting for a Core i9-13900K model. From a consumer standpoint, unless a good custom water cooling loop is employed with the Core i9-13900KS, then the benefits of going for the higher bin special SKU over the regular Core i9-13900K aren't worth it. 

Intel Core i9-13900KS: Fastest Desktop Processor, But Be Prepared To Spend $$$ on Cooling

It has been said many times that achieving peak performance levels is an expensive quest, and the Core i9-13900KS has a premium price of $729 (retail), while the Core i9-13900K is $600 at the time of writing. But that's not the whole picture...

There are benefits to be had from the Core i9-13900KS, and it is precisely what Intel claims it to be, the world's fastest desktop processor with core clock speeds of up to 6 GHz. This is prevalent in single-threaded applications, but once more than two cores are loaded, it reverts to the all-P-core frequency of 5.6 GHz; this is still very fast.

This is because Intel's Extreme Power Delivery Profile allows the chip to run at 320 W, giving more power headroom for the cores to do their thing. It's worth noting that Intel's integrated automatic overclocking technologies work well, including Turbo Boost Max 3.0, which is set to 5.8 GHz on two P-Cores. In contrast, Intel's Thermal Velocity Boost (TVB) technology allows the same two P-cores to push further to 6 GHz (200 MHz more) where thermals allow it. 

Intel doesn't clarify that keeping temperatures in line so Thermal Velocity Boost can sustain 6 GHz does require superior cooling; CLC coolers will not do; custom water cooling is needed at a minimum for maximum performance. Of course, another avenue to reduce temperatures could be to under-volt the CPU V-Core slightly, although this isn't something novice users should consider, and the Core i9-13900KS with TBM 3.0 and TVB work well out of the box.

With their KS processors, Intel has seemingly abandoned any semblance of power and thermal efficiency and instead gone into the realms of max power and charge ahead at any cost territory. This makes purchasing the Core i9-13900KS heavily dependent on the system it will be installed into, including having ample cooling and power supply capabilities to let it stretch its legs. Pulling 360 Watts is no small amount of energy for the processor to contend with without factoring any of the above into the equation.

The Intel Core i9-13900KS is a feat of Intel's push to offer the fastest and, ultimately, best desktop processor on the market. Still, the $729 street price for marginal gains at best, even with a premium 360mm AIO CPU cooler, makes it hard to unequivocally recommend. That said, for users with deep pockets for a suitable chassis, a quality Z790 (or Z690) motherboard, and a premium custom water cooling loop, the Core i9-13900KS is the clear choice if you want to have the best of the best from Intel.