Clock Frequencies

The following chart shows how well the processor sustains its clock frequency and which boost clock speeds are achieved at various thread counts. This test uses a custom-coded application that mimics real-life performance—it is not a stress test like Prime95. Modern processors change their clocking behavior depending on the type of load, which is why we provide three plots with classic floating point math, SSE SIMD code, and modern AVX vector instructions. Each of the three test runs calculates the same result using the same algorithm, just with a different CPU instruction set.



The E-Core side of this chart (threads 17 to 32) can be somewhat misleading. It looks like the cores run at increasingly slower frequencies as the load goes up, but that's not the case. The frequency plotted is the average of all the P-Cores active, plus more and more E-Cores, which all run at a lower frequency than the P-Cores, which drags down the average.

That's why I tested E-Core frequency scaling separately in the chart below.

Overclocking

Overclocking the Core i9-14900KS is easy, thanks to its unlocked multiplier. The biggest problem is the heat though, even at stock you'll be reaching 100°C and higher. Overclocking the 14900KS means setting the thermal limit to 115°C up from 100°C, and then figuring out what's the highest voltage you can give the CPU without hitting throttling at 115°C, depending on your cooling solution. Switching from air to our Arctic AIO helped with controlling the heat. Our maximum all-core OC is 5.8 GHz on the P-Cores, plus 4.6 GHz on the E-Cores, 100% stable. This still isn't enough to beat the stock configuration in lighter applications and most games, because here the CPU will boost two cores up to 6.2 GHz. You can work around this a bit by running a per core overclock, based on how many cores are active, for example a x63 multiplier for 1 and 2 cores, and x58 or x59 for all loads higher than that. Beyond that there are plenty of other overclocking strategies for Raptor Lake, which involve Thermal Velocity Boost, Voltage/Frequency curves and Loadline tweaking.

Intel also has a new feature in their XTU tuning utility, which uses AI to find optimized overclocking settings. This worked very well in our testing and gives a good starting point in a few minutes. Under the hood it uses Linpack as stability test and will tweak not only the multiplier, but also power limit, TVB settings and others. Memory clocks are not tuned though, and the software requires VBS to be disabled (which is enabled by default on all Windows installations).