I am torn on i9-13900k vs 7900X. Anyone have linux workstation experience with one of these? Missed a big discount on the 7900 yesterday (prime day) but been leaning towards Intel. Just wondering how Linux does with the perf vs. efficiency cores.
I also find it amusing, although not professionally relevant, to experiment with the unusual abilities of the 13900K that descend from its Atom lineage: clusters of 4 e-cores that share L2, and the WAITPKG ISA extension that makes switching threads extremely fast. On the other hand the 7900X has AVX-512 and I would rather have that instead.
On the 13900K...
At home, I have a 13900K (128G 4090 8T+8TSSD) and use Mathematica often for personal use. I installed it intially in Windows 11 Pro and got abysmal performance in benchmarks (worse than 12900 equivalent processor). With help from Wolfram customer support, I switched to Linux (Ubuntu): the performance is on par with what I'd expect.
My hypothesis is that either the Windows scheduler for Windows 11 Pro optimizes for a different performance point than Linux, or that it was oblivious of performance vs. efficiency core (13900K has double the efficiency cores of the previous generation, so if you pick randomly you have a lot more chances to end up in a slow core).
This was in the previous minor release of Mathematica, I hope they implemented a workaround in the latest version. I don't think it was a Mathematica bug, but an OS-level problem (I haven't tried, but I can it would be easy to check): many report that stable diffusion works better on Linux than Windows.
My personal toy project was a reinforcement learning thing, for which the CPU was the bottleneck on Windows (performance on par with MacStudio M1 Max) and I saw nearly 2x improvement switching to Linux.