[Hardware] Intel Core i9-12900KS Review: The Fastest Gaming Chip Ever

[D.CraZy]

Intel's Special Edition hits 5.5 GHz with ease.

Intel's Core i9-12900K arrived last year as the fastest gaming CPU we've ever tested, but the new Special Edition Core i9-12900KS pushes the Alder Lake family up to a blistering 5.5 GHz, a record high for PCs, making it the fastest desktop PC chip in all categories. The 12900KS comes to market on April 5, but we snagged a chip to put it to the test ahead of the final launch.

But that isn't the final word yet: AMD has its $449 Ryzen 7 5800X3D waiting in the wings. The 5800X3D comes with the first 3D-stacked SRAM for desktop PCs, granting the chip a whopping 96MB of L3 cache that AMD says will take back the crown of the best CPU for gaming when it arrives on April 20.

Make no mistake, Intel's goal with the 12900KS is to cement itself atop the performance charts to cut off the 5800X3D before it even arrives on the market. Intel aims to accomplish this feat by leveraging the 12900K's existing 16-core 24-thread design, but with a higher binning that supports speeds up to 5.5 GHz on two cores and up to 5.2 GHz for all-core boosts, both enabled by adding in Intel's most advanced boosting tech.  

That comes at the cost of extra power, though: The Core i9-12900KS comes with a 150W processor base power (PBP), a record for a mainstream desktop processor. As we'll show below, it's an understatement to say the 12900KS runs hot, so it requires the beefiest of cooling solutions. However, as we'll detail, some of that tendency to run hot is by design and it enables a new level of performance for desktop PCs.

The speedy 12900KS is sure to satisfy deep-pocketed performance addicts, and it comes with the same overall feature set as the 12900K, like support for DDR5 and PCIe 5.0 on the desktop. AMD can't match that type of connectivity until its 5nm Ryzen 7000 ‘Raphael’ Zen 4 CPUs arrive later this year. The 12900KS also comes with Alder Lake's new hybrid x86 design that combines eight big and fast Performance cores (P-cores) with two four-core clusters of small and powerful Efficiency cores (E-cores) that chew through background processes.

Intel's Core i9-12900K catapulted the company back to the top of the performance and value charts after the beating it took at the hands of AMD's Ryzen 5000 family, but AMD is finally firing back with seven new chips of its own that will come to market this month. Intel's Core i9-12900KS is Intel's brazen 'power and price be damned' attempt at keeping the performance crown at all costs, just like we saw with Intel's only other 'Special Edition' chip, the Core i9-9900KS.

All of this means that while Intel's 12900KS delivers strong performance that leads our CPU benchmark hierarchy, its hefty $739 premium might not be as good of a buy for gaming as AMD's $449 5800X3D. However, the eight-core 5800X3D won't be able to keep pace in any other type of work, as the 16-core Core i9-12900KS has a core count and frequency advantage. Here's how Intel's latest Special Edition stacks up. 

Intel Alder Lake-S Core i9-12900KS Specifications and Pricing

The Core i9-12900KS is a Special Edition chip, but Intel hasn't said if it will only produce a limited number as it did for the 'Limited Edition' Core i7-8086K. However, we do know that the 12900K's thousand-unit price (effectively the wholesale MSRP) lands at $739, so we can expect to see these chips at retail for around $775 to $800 at launch.

That's a surprising premium over the 16-core 32-thread Ryzen 9 5950X that now retails for around $600, and it's also much more expensive than the $449 Ryzen 7 5800X3D that AMD says will be faster at games. This means there's a good chance we could see the Core i9-12900KS sell for lower than its suggested pricing after the initial demand is satisfied. 

The Core i9-12900KS is functionally the same as the Core i9-12900K, which you can read much more about here. We also have deep-dive coverage of the Alder Lake SoC design and core microarchitectures here, along with a broader overview in our Alder Lake all we know article.

The 12900KS has eight P-cores just like the 'K' version, but they now boost up to 5.5 GHz (300 MHz increase) if certain conditions are met. The chip also features eight E-cores that also receive an extra 100 MHz of clock speed. Intel has a total of five boost technologies (deeper explanation here), but the standard Core i9-12900K only supports two of them. The 12900KS supports all five to deliver higher clock speeds. 

Intel's single-core Thermal Velocity Boost (TVB) tech allows the two fastest favored cores to boost to 5.5 GHz if they are below 70C, while the all-core TVB supports 'up to' the frequencies in the table above. The 12900KS also has Adaptive Boost Technology, allowing dynamic all-core turbo frequency adjustments when four or more cores are active. This feature doesn't have a guaranteed boost threshold — it will vary based on chip quality, your cooler, and power delivery. Think of Intel's Adaptive Boost Technology (ABT) much like a dynamic auto-overclocking feature that applies to all-core boosts, but using it doesn't void the warranty.

These higher clock speeds require more power. As a result, Intel has increased the Processor Base Power (PBP) to 150W, an increase of 25W over the Core i9-12900K. However, the Maximum Turbo Power (MTP) value, which represents the highest power level during boost activity, remains the same at 241W. Naturally, all bets are off when you remove the power limits, which happens by default on most high-end motherboards.

All Alder Lake chips support DDR4-3200 or up to DDR5-4800 memory, but caveats apply. Alder Lake chips expose up to 16 lanes of PCIe 5.0 (technically for storage and graphics only, no networking devices) and an additional four lanes of PCIe 4.0 from the chip for M.2 storage. The 12900KS also comes armed with the UHD Graphics 770 engine with 32 EUs that run at a 300/1550 MHz base/boost, just like the standard 12900K. However, there is no graphics-less F-series variant. 

Test Setup

We tested the 12900KS's boosting, power and thermal characteristics extensively, finding that the chip easily and frequently boosts to 5.5 GHz. It also sustains up to a 5.2 GHz boost clock on all P-cores, though not under all conditions. The peak 305W of power consumption we recorded has an impact on thermals, which regularly stay at 100C under heavy multi-core loads. That's because Intel's auto-overclocking ABT feature is designed to extract the full performance available within the spec'd temperature range. You can find that testing after the game and application benchmarks below.

Alder Lake's Thread Director technology steers threads to the correct type of cores. This tech works best with Windows 11, so we use that for testing. It's important that you know that these chips can suffer in very few multi-threaded workloads in Windows 10. You can correct those issues either via command-line utilities or third-party software, like Process Lasso, and receive the full expected performance.

Aside from a few errant programs, the overall trends between Windows 10 and 11 are similar. As such, we're not going to post the redundant Windows 10 benchmarks in this article. We also stuck with DDR4 for this round of testing, as overall performance trends are generally the same between DDR4 and DDR5. We have a deeper dive into what that looks like in our initial 12900K review. We tested in the following two configurations:

Core i9-12900KS NoPL DDR4: Corsair H115i 280mm water cooler, power limits removed, memory at DDR4-3200 in Gear 1 mode

Core i9-12900KS StockPL DDR4: Corsair H115i 280mm water cooler, Intel recommended stock power limits (150/241W), Stock DDR4-3200 in Gear 1

Core i9-12900K: Corsair H115i 280mm water cooler, power limits removed, memory at DDR4-3200 in Gear 1 mode

Intel Core i9-12900KS Gaming Benchmarks — The TLDR

As usual, we're testing with an Nvidia GeForce RTX 3090 to reduce GPU-imposed bottlenecks as much as possible, and differences between test subjects will shrink with lesser cards or higher resolutions. Because most of the titles below show little meaningful differentiation at higher resolutions, we only tested four of the seven titles at 1440p.

The Core i9-12900KS is now the fastest gaming chip in the world, but only by a slight 2.7% gain over the vanilla 12900K in our cumulative 1080p performance measurement. However, we do see a larger 6.9% gain in the 99th percentile framerates, implying a smoother gaming experience. It is noteworthy that a few of our tested titles are approaching a GPU bottleneck at 1080p, so we might see larger performance deltas when new, more powerful GPUs arrive later this year. However, due to the GPU bottleneck, the difference between the two chips is imperceivable at QHD.

It's noteworthy that we typically test with the power limits fully removed for our standard measurements, so the 12900K in the above charts is running beyond Intel's 'recommended' power settings but remains within warranty. The 12900KS's 5.5 GHz boost frequently engages in any configuration, contributing to a dead tie between the two KS configurations in our cumulative measurement of performance at 1080p.

Moving over to 1440p brings a GPU bottleneck into the equation, so the performance deltas between the chips shrink tremendously. However, those results provide good perspective if you game at higher resolutions and don't plan to upgrade your GPU before buying your next CPU. 

Flipping through the 99th percentile charts for both resolutions also shows larger deltas, but we have to view those with caution as Windows 11 is still young and suffers from more framerate variability than our Windows 10 test platform. This could result from yet-to-be-updated game code, the relatively new graphics drivers for Windows 11, or some other combination of factors that could be smoothed out in the future.
The Core i9-12900KS carves out a win in our game testing, but that 2.7% of extra performance at 1080p comes with a 25% price increase. The 12900KS also can't circumvent the general laws of the universe and make the GPU any faster, so you won't see any noticeable gain at higher resolutions or with games that are already bottlenecked by the GPU. That lack of improvement is disappointing, given that most folks that purchase this expensive chip won't be gaming at lower resolutions.
The competition between Intel and AMD is much closer now, so it's best to make an informed decision based on the types of titles you play frequently. Be sure to check out the individual tests below.

3DMark, VRMark, Chess Engines on Intel Core i9-12900KS

Synthetic benchmarks don't tend to translate well to real-world gaming, but they do show us the raw amount of compute power exposed to game engines. It's too bad most games don't fully exploit it.

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