Core i9-12900KS Review: Intel’s Fastest Alder Lake CPU Tested
When the Windows installation was complete, we installed all of the drivers necessary for our components, disabled Auto-Updating and Windows Defender, and installed all of our benchmarking software. When that process was done, we performed a disk clean-up, cleared any temp and prefetch data, and optimized all of the SSDs using Windows' built-in utility. Finally, we enabled Windows Focus Assist to minimize any potential interruptions and let the systems reach an idle state before invoking a test.
Our Test Systems: Revamped For Windows 11

Geekbench v5.4.1 CPU Compute Benchmark

The Core i9-12900KS puts up top scores in Geekbench. In both the single and multi-threaded tests, the chip leads the pack, thanks to the strong performance of its P-cores and higher-clocks. The Core i9-12900K already offered excellent performance here, and the KS just kicks things up a notch.
UL PCMark 10 Benchmarks
Next, up we have some full-system testing with PCMark. We're reporting all test results from the PCMark 10 benchmark suite, including the Essentials, Productivity, Digital Content Creation and and total PCMark score. The Essentials test covers workloads like web browsing, video conferencing and app start-up times, while Productivity tests everyday office apps from spreadsheets to word processing. Finally, the Digital Content Creation test evaluates performance of a machine with respect to photo and video editing, as well as rendering and visualization.
The Core i9-12900KS also led the pack in our PCMark 10 tests. Here, its higher clocks give it a slight edge over in the Core i9-12900K in the individual tests, which culminate in the best overall score of the bunch.
Bapco Crossmark Testing
Crossmark is a new cross-platform benchmark from Bapco that's available for Windows, Android, iOS and MacOS. Like PCMark, Crossmark measures overall system performance and using real-world applications. It characterizes system responsiveness as well, based on the results of its Creativity and Productivity benchmarks.
Are you beginning to see a pattern yet? In the BapCo CrossMark benchmark, the Core i9-12900KS also offers up class-leading performance. Thanks the to Alder Lake architecture and higher-frequencies, the Core i9-12900KS is particularly strong in the responsiveness test versus competing AMD processors.
Browser & Web App Benchmarks: Jetstream 2 And Speedometer 2
These benchmarks measures performance of an array of browser-based technologies used on modern, rich web applications. Scores in these benchmark are an indicator of the performance users would see when browsing the web and running advanced web apps. All of the systems were tested using the latest version of Microsoft's Edge browser, with default browser settings, on a clean, fully-updated install of Windows 11.


7-Zip Data Decompression Tests

There is no overcoming the additional cores and threads of AMD's high-end Ryzen processors in the 7-Zip decompression benchmark. Here, the Core i9-12900KS trails both Ryzen 9 processors, but offers a measurable lead over the Core i9-12900K.