Intel Core i9-12900KS review: Intel’s fastest gaming CPU to date

If Intel’s recent take on the RPS guide to the best gaming CPUs wasn’t clue enough, their latest 12th Gen Alder Lake chips are the real deal – especially when it comes to pure gaming performance. In a way, this should make the newly launched Core i9-12900KS the truest deal of all: it’s structurally identical to the Core i9-12900K, originally the top CPU in the series, but made with an even more sophisticated binning process. A component of the highest quality components, if you will, and as such it can surpass the Core i9-12900K’s max boost clock speed of 5.2GHz to reach a searing 5.5GHz.

Higher per-core speeds are usually good news for gaming, and it’s not just at the top end that the Core i9-12900KS makes improvements: its eight larger, lower-performing cores (P-Cores) get a 200MHz increase in base clock, up to up to 3.4 GHz, and its eight smaller efficiency cores (E cores) increase by 100 MHz up to 2.5 GHz. The end results very often back up Intel’s claims that this is the “world’s fastest desktop processor”, although it’s also sort of a CPU version of the RTX 3090 Ti graphics card: technically better, but maybe not big enough to justify it cheaper alternatives.

Unfortunately, sampling lag prevented me from testing the Core i9-12900KS alongside the AMD Ryzen 7 5800X3D, which the red team also calls the world’s fastest gaming CPU (albeit using a completely different method: charging). cache rather than maxing out core speeds). What I can It can be said that the Core i9-12900KS outperforms all other well-known Ryzen and indeed Intel Core CPUs as desktop multitaskers. In the Cinebench R20 benchmark, its single-core score of 811 and multi-core 11,019 places it well ahead of the Core i9-12900K (756 and 10,519 respectively) and the AMD Ryzen 9 5950X (639 and 10,189 respectively).

They also neatly demonstrate the great merits of the two newer Intel chips: the higher core clock speeds are responsible for the monster single-core performance, while its multi-core capabilities come from the characteristic Alder Lake combination of P-Cores and E-Cores . Like most of its 12th Gen peers, the Core i9-12900KS can more efficiently shift small chunks of the workload to the cores that are best suited to them – heavy work goes to the P cores, lighter work goes to the E cores . If you also need your gaming PC to juggle media editing or heavy coding, the benefits are obvious.

A bar chart showing the gaming benchmark scores of the Intel Core i9-12900KS alongside those of competing CPUs.

A bar chart showing the gaming benchmark scores of the Intel Core i9-12900KS alongside those of competing CPUs.

When it comes to gaming, the Core i9-12900KS usually comes out on top. Take a look at these benchmark results recorded with an RTX 2080 Ti GPU: you can see for yourself that it’s consistently ahead of both the Core i9-12900K and the Ryzen 9 5950X. The latter was tested with DDR4 RAM, not DDR5 like all four 12th Gen Intel CPUs, but I’ve found DDR5 to be neither significantly better nor worse than DDR4 on current hardware and games.

Aside from an insanely good Assassin’s Creed Valhalla performance from the Intel Core i5-12400F (I’ve retested this multiple times and yes, it’s legit), the Core i9-12900KS either leads or catches up to its rivals in every single game. It’s definitely the fastest gaming CPU Intel has ever made; the fastest in the world? That’s down to the Ryzen 7 5800X3D, but I’d say the core has a very good shot.

There is a difference between being the fastest and the best. As with the RTX 3090 Ti, the underlying fun killer is money: when the Core i9-12900KS costs £720/$750, about £120/$150 more than the Core i9-12900K, you’d expect the gap in gaming performance to be around to reflect this difference.

An Intel Core i9-12900KS CPU held between finger and thumb.

It doesn’t. It’s all well and good, averaging 10fps more than the S-less model in Shadow of the Tomb Raider, but at 160fps and up you can hardly tell the difference. And in almost every other game there is either a negligible difference of 2-3 fps or none at all. Assassin’s Creed Valhalla stretches the Core i9-12900KS’ lead a bit, but an extra 6fps just isn’t worth another £120.

And that’s just a comparison with the other Core i9. Yes, technically they tend to drop a few more FPS, but the relatively cheap Core i5-12600K and Core i5-12400F are competitive with the Core i9-12900KS in everything but Forza Horizon 4. And maybe Shadow of the Tomb Raider, although in both cases the high frame rates mean that deviations from 10 to 20 fps are not as visible as at lower levels. Elsewhere, it’s more single-digit differences that make the Core i9-12900KS’s value proposition even worse.

Aside from paying more than you have to, choosing the Core i9-12900KS would also mean using more power than you have to. Its base power consumption – not even its maximum power draw – is 150W, 25W more than the Core i9-12900K and Core i5-12600K and a voracious 85W more than the Core i5-12400F. The Core i9-12900KS, unlike the Core i5-12400F, is unlocked for overclocking, but that would also put you in a sticky spot with heat.

An Intel Core i9-12900KS CPU installed in a motherboard.

I tested the Core i9-12900KS with an Asus ROG Ryujin II 360, which is a fairly expensive (but effective) AIO liquid cooler. Gaming doesn’t get dangerously hot, with the warmer P-cores mostly staying in the 44-60°C range. But that’s up to 10C hotter than the Core i9-12900K, and the P-Cores’ 71C peak was also higher. So the cheaper chip is easier to overclock with liquid cooling, although both CPUs could also easily hit 100C during Cinebench R20 runs (which I like to call an oh-oh temperature). At serial speed!

I’d say this isn’t too much of a deal if you’re just building a gaming PC and not a multi-purpose workstation. If that’s the case, though, you’re better off forgetting about the Core i9s and just getting a Core i5-12600K (or Core i5-12400F) instead. The appeal of the Core i5-12900KS as a carefully crafted record holder isn’t as strong as the satisfaction you get by saving hundreds on a processor with essentially identical performance.