INTEL CORE i9 12900KS Alder Lake CPU Review

In some ways, Core i9-12900KS is Intel’s answer to the Ryzen 7 5800X3D’s gaming performance – it’s essentially a cherry-picked Core i9-12900K with a massive peak boost frequency of 5.5GHz. Cherry picking never comes cheap, though. Speed binning only results in a small number of chips that are capable of having all their parts enabled and running at high clock speeds, so buying this CPU involves forking out an extra $200 over the already pricey Core i9-12900K.

Last month we were doing some very early testing on the CPU, though, and this time we’re using the latest BIOS from Asus, which has been specifically designed to offer the best performance with the Core i9-12900KS. In short, this means giving it more power, and sure enough, our test system peaked at a massive 489W at load, which was over 160W than it drew with the Core i9-12900K installed. This power draw is borderline obscene, as were the CPU temperatures, which regularly topped 90°C, despite the fact we were using a custom water-cooling loop with the latest LGA1700 waterblock from EK.

You’d hope, then, that performance was unmatched, and thankfully we weren’t disappointed. The Core i9-12900K accelerated its way to offering a massive 86,284 points in our lightly threaded image editing test, and no other CPU came close to this result, even when overclocked.

Benchmarks - INTEL CORE i9 12900KS CPU

The story in our heavily multi-threaded Handbrake video encoding test was similar, with the Core i9-12900KS scoring 1,137,489 compared to 1,061,918 for the Core i9-12900K and 1,029,189 for the Ryzen 9 5950X. Both those CPUs needed to be overclocked up to the hilt to beat the Core i9-12900KS in Cinebench too, where its stock speed score of 28,645 was over 3,000 points higher than that of the Ryzen CPU, and over 1,000 points clear of the Core i9-12900K.

The Core i9-12900KS was also the only Intel CPU that was able to keep up with the Ryzen 7 5800X3D in games, mostly matching it in Far Cry 6 and offering a 99th percentile frame rate that was around 10fps higher than that of other Intel CPUs on test. It also grabbed the top spot in Watch Dogs: Legion, and even held on to that spot when other CPUs on test were overclocked too. With the temperatures we saw from this CPU at stock speed, we didn’t dare attempt a manual overclock on it, but it’s worth playing with power limits, as they can rein in power consumption (and heat) at the expense of some performance.


Base frequency P-Core 3.4GHz, E-Core 2.5GHz
Max boost frequency P-Core 5.5GHz, E-Core 
Core Alder Lake
Manufacturing process 10nm
Number of cores 8 x P-Cores, 8 x E-Cores 
(24 threads)
IGP Intel UHD Graphics 770
Hyper-Threading Yes
Cache 30MB L3, 14MB L2
Memory controller Dual-channel DDR4 and 
Packaging LGA1700
Thermal design power (TDP) 150W
Features Thermal Velocity Boost, Turbo Boost 
Max Technology 3, Turbo Boost 2, FMA3, F16C, 
SHA, BMI / BMI1 + BMI2, AVX-512, AVX2, AVX, 


If you must have the fastest mainstream desktop CPU, and don’t care how much it costs, the Core i9-12900KS won’t disappoint. Using a honed BIOS that was freely available from Asus, it was a monster, even outstripping the Core i9-12900K by significant margins in some tests. It needs a big wallet and an even bigger cooling system, but given its thermals and power consumption, as well as it’s exorbitant price tag, we can’t recommend it outright as a chip that’s worth buying. It’s a ridiculous CPU, but if you have the money, PSU and cooling system for it, you won’t be disappointed.

+ Pros
+ Chart-topping gaming performance 
+ Incredible in lightly threaded and multi-threaded tasks 
+ Keeps up with the best AMD has to offer 

- Cons
- Massively power-hungry 
- Runs extremely hot 
- Enormous price tag

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