AVX-512 Performance Comparison: AMD Genoa vs. Intel Sapphire Rapids & Ice Lake

Across all of the benchmarks run with AVX-512 on/off, when AVX-512 was enabled for the Xeon Platinum 8380 2P "Ice Lake" server and running these AVX-512 heavy workloads it saw a ~175MHz drop on average to the peak CPU frequency. Now with Sapphire Rapids this is no longer the case but the peak CPU frequency was similar with/without AVX-512. As shown previously, AMD EPYC Genoa also doesn't experience the AVX-512 downclocking. With Ice Lake it wasn't too bad to begin with unlike the AVX-512 Skylake days.

When looking at the CPU power consumption across all of the AVX-512 benchmarks carried out, when using AVX-512 on the Xeon Platinum 8380 it increased the average power consumption by 24% (365 vs. 451 Watts for the two CPU configurations). Meanwhile with the Xeon Platinum 8490H server the average power consumption was basically the same. There wasn't the EPYC 9654 results here due to a test interruption, but Zen 4 generally enjoys similar power consumption when AVX-512 is enabled.

When taking the geometric mean of all the raw AVX-512 benchmark results in this article, the Xeon Platinum 8380 2P "Ice Lake" performance went up by 34% with the AVX-512 enabled run where as the Xeon Platinum 8490H 2P "Sapphire Rapids" AVX-512 performance improved by 44% and the EPYC 9654 2P "Genoa" performance was up by 21% with AVX-512. Sapphire Rapids not only enjoyed much larger uplift from AVX-512 compared to with Ice Lake, but also a big win for power efficiency.

The geometric mean also shows how important AVX-512 is for the success of 4th Gen EPYC Genoa in being competitive against 4th Gen Xeon Scalable for HPC workloads. Had Zen 4 not added AVX-512, the EPYC 9654 2P AVX-512-disabled results came out just behind the Xeon Platinum 8490H 2P with AVX-512 enabled. A Zen 4 server processor without AVX-512 would have been a neck-and-neck race between Sapphire Rapids and Genoa in more workloads. But instead the EPYC 9654 2P with AVX-512 came out 19% faster than the Xeon Platinum 8490H processors in this set of benchmarks.

I'm left rather surprised that Intel hadn't more notably promoted their AVX-512 improvements with 4th Gen Xeon Scalable at launch, but in any case it's good seeing AVX-512 providing greater uplift while also not having the significant impact on power consumption that was seen with earlier generations of AVX-512 processors. This can immediately be of benefit to a lot of existing software out there compared to having to adapt to make use of AMX and the new accelerators. Hopefully this more efficient AVX-512 with Sapphire Rapids paired with AMD Zen 4 CPUs now having AVX-512 will lead to more software developers considering AVX-512 optimizations for their software.