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.

Overclocking

Overclocking the Ryzen 9 7900 works exactly the same as on the -X suffix AMD processors. Unlike Intel, AMD does not lock overclocking on these models, it's all there—unlocked multiplier, adjustable power limits, memory settings, everything.

For overclocking I dialed the voltage up to 1.30 V, which is about the maximum I could run Prime95 at and not overheat by crossing 115°C. I then dialed the clocks up until the system was unstable. While I could boot and run many lighter workloads, including games at well 5.4 GHz, heavy loads kept crashing the system. Ultimately I settled for 5.3 GHz, which is an "ok" overclock, considering a max boost rating of 5.4 GHz. As our performance results show, in light loads, the "PBO Max" config will achieve better performance, because it can reach clocks higher than 5.3 GHz, even if only briefly. In other workloads, like rendering, the 5.3 GHz all-core ends up with higher clocks, because PBO is more cautious in that setting.