As far as top-tier CPU SKUs go, Intel's Core i9-12900KS processor sits in noticeably sharp In contrast to the launch of AMD's Ryzen 7 5800X3D processor with 96 MB of 3D V-Cache. Whereas AMD's over-the-top chip was positioned as the world's fastest gaming processor, for their fastest chip, Intel has kept their focus on trying to beat the competition across the board and across every workload.

As the final 12th Generation Core (Alder Lake) desktop offering from Intel, the Core i9-12900KS is unambiguously designed to be the powerful one. It's a "special edition" processor, meaning that it's low-volume, high-priced chip aimed at customers who need or want the fastest thing possible, damn the price or the power consumption.

It's a strategy that Intel has employed a couple of times now – most notably with the Coffee Lake-generation i9-9900KS – and which has been relatively successful for Intel. And to be sure, the market for such a top-end chip is rather small, but the overall mindshare impact of having the fastest chip on the market is huge. So, with Intel looking to put some distance between itself and AMD's successful Ryzen 5000 family of chips, Intel has put together what is meant to be the final (and fastest) word in Alder Lake CPU performance, shipping a chip with peak (turbo) clockspeeds ramped up to 5.5GHz for its all-important performance cores.

For today's review we're putting Alder Lake's fastest to the test, both against Intel's other chips and AMD's flagships. Does this clockspeed-boosted 12900K stand out from the crowd? And are the tradeoffs involved in hitting 5.5GHz worth it for what Intel is positioning as the fastest processor in the world? Let's find out.

Below is a list of our detailed Intel Alder Lake and Z690 coverage:

As a quick recap, we've covered Alder Lake's dual architectural hybrid design in our Core i9-12900K review, including the differences between the P (performance) and E (efficiency cores). The P-cores are based on Intel's high-performing Golden Cove architecture, which provides solid single-threaded performance. Meanwhile, the Gracemont-based E-cores, although lower-performing on their own, are smaller and draw much less power, allowing Intel to pack them in to benefit multi-threaded workloads without blowing the chips' power and thermal budgets.

The Intel Core i9-12900KS: The World's Fastest Processor

Not just content with having a solid selection of premium 12th generation Core series processors, including the then flagship Core i9-12900K, Intel a few months ago unleashed the Core i9-12900KS to the market. Primarily targeted at gamers and enthusiasts who need the very best of performance, the Core i9-12900KS is essentially a high bin version of the Core i9-12900K, but with a few (not so subtle) differences.

Based on the same Alder Lake die, both 12900Ks share the same core and thread count (8P+8E). Instead, the most significant difference comes in the speed: the Core i9-12900KS has a whopping 5.5 GHz boost core on its Performance (P) cores, which is 300 MHz higher than the regular K chip. Meanwhile the base frequencies are also improved by 200 MHz higher, leading to a chip that offers 3.4 GHz base and 5.5 GHz boost clockspeeds. That makes the Core i9-12900KS the fastest desktop processor hat Intel has ever created in terms of out-of-the-box core frequency. Even the Efficiency (E) cores have been clocked higher for this SKU, with a 100 MHz bump on both the base and boost frequencies, putting the E cores at 2.5 GHz base and a 4.0 GHz boost.

Intel 12th Gen Core i9 Series
Alder Lake
AnandTech Cores
i9-12900KS 8+8 2500 4000 3400 5500 30 770 150 241 $739
i9-12900K 8+8 2400 3900 3200 5200 30 770 125 241 $589
i9-12900KF 8+8 2400 3900 3200 5200 30 - 125 241 $564
i9-12900F 8+8 1800 3800 2400 5100 30 - 65 202 $464
i9-12900 8+8 1800 3800 2400 5100 30 770 65 202 $489
i9-12900T 8+8 1000 3600 1400 4900 30 770 35 106 $489

The engineering tradeoff to the bump in core frequencies on both the Performance (P) and Efficiency (E) cores is that the Core i9-12900KS draws more power, with a base TDP of 150 W and a boost TDP of up to 241 W. This is an increase of 25 W for the base TDP versus the original Core i9-12900K processor, which from our experience, is already a hot running processor that can draw some serious power when overclocked. And there's room to go higher still – like other K-series chips, the 12900KS is multiplier unlocked, meaning users can attempt to overclock these chips even further.

Focusing on price, the Intel Core i9-12900KS is officially priced at $739 in for 1000 chip orders. Street pricing, in turn, is almost spot-on, with Amazon and Newegg charging $735 each. Officially this puts a $150 premium on the top-tier 12900KS, while comparing street prices it's closer to about a $175 premium right now. This also puts it $235 more expensive when directly compared to AMD's most expensive desktop chip, the Ryzen 9 5950X processor ($499), and just shy of $300 over the Ryzen 7 5800X3D ($439). Suffice it to say, when it comes to 'halo' products such as this, any notions or dreams of value typically go out of the window, and users that are looking for the fastest and greatest going to be expected to dig deep in to their wallets. 

The Core i9-12900KS hitting 5.5 GHz on P-core 4 and 5, rest of the P cores at 5.2 GHz

And while there's a significant price difference between the two, make no mistake: the Core i9-12900KS was created to go directly up against AMD's impressive Ryzen 7 5800X3D and its 96 MB of 3D L3 V-Cache. Pitched as the ultimate gaming processor, the Ryzen 7 5800X3D, as we have seen, is very potent in gaming, often vaulting to the top in CPU-limited workloads. Even factoring in the 5.5 GHz performance core boost frequencies, the large pool of L3 cache on the 5800X3D will shine in games that can utilize that extra cache. In the titles where additional cache doesn't influence performance, the insane clock speeds of 5.5 GHz will shine, or so that is the hope for Intel here.


The most significant benefit of Intel's Alder Lake special edition chip is that it isn't a one-trick pony; because this SKU is based on across-the-board clockspeed increases, it offers some serious horsepower for computational tasks. This is where we saw the AMD Ryzen 7 5800X3D lag behind the competition, as L3 cache typically doesn't influence the performance of rendering, encoding, and transcoding as pure core grunt does. It will be interesting to see how the Core i9-12900KS stacks up against the i9-12900K in our computational suite while it will be going metaphorically head to head with the Ryzen 7 5800X3D in our gaming suite.

Test Bed and Setup

Although there were some problems initially with the Intel Thread Director when using Windows 10 at the launch of Alder Lake, any core scheduling issues are entirely negated by using the latest Windows 11 operating system. The Intel Thread Director works in tandem with Alder Lake to assign the right P-cores and E-cores to different tasks based on the complexity and severity of the workload. We also test the Core i9-12900KS with DDR5 memory at JEDEC specifications (DDR5-4800 CL40). We are also using Windows 11, which we are using now for CPU and motherboard reviews as we advance into the rest of 2022 and beyond.

For our testing, we are using the following:

Alder Lake Test System (DDR5)
CPU Core i9-12900KS ($735)
8+8 Cores, 24 Threads
150W Base, 241W Turbo
Motherboard MSI Z690 Carbon WI-FI
Memory SK Hynix
2x32 GB
DDR5-4800 CL40
Cooling ASUS ROG Ryujin II 360mm AIO
Storage Crucial MX300 1TB
Power Supply Corsair HX850 
GPUs NVIDIA RTX 2080 Ti, Driver 496.49
Operating Systems Windows 11 Up to Date

All other chips for comparison were run as tests listed in our benchmark database, Bench, on Windows 10.

CPU Benchmark Performance: Power, Office, And Science
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  • Dante Verizon - Sunday, July 31, 2022 - link

    Honestly, iGPU performance seems abnormal.. What's going on
  • tygrus - Sunday, July 31, 2022 - link

    What's the avg power or task energy while doing different workloads? eg. Browser/office apps, video playback, video encoding/Transcoding, MT technical.
  • MDD1963 - Monday, August 1, 2022 - link

    AT is really on top of reviewing the fastest CPUs within less than 4-5 months of their releases...!!! :/
  • MDD1963 - Monday, August 1, 2022 - link

    Doing CPU comparisons with only a 2080Ti is bogus.....(good on ya'll for not using a GTX1060, however!)
  • Alistair - Monday, August 1, 2022 - link

    it's fine, just use 720p instead of 1080p, you'll get higher FPS with a 2080 Ti at 720p than a 3090 Ti at 1080p
  • gallon6341 - Saturday, September 17, 2022 - link

    In this gen I am very impressed with the i5 12400f.

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