Post
Topic
Board Mining (Altcoins)
Re: XMR RandomX mining with Ryzen 3900x
by
shinji.link
on 03/04/2021, 19:31:30 UTC
I wasn't 100% sure what you meant by next line prefetch. Did you mean disabling hardware prefetch in the BIOS or setting scratchpad prefetch mode in the XMRig config.json file to 0 from 1?

Thanks, RAM timing did better than I expected, however, one has to know what one is doing to get it right.

Next line prefetch is when the CPU speculatively prefetches the next cache line to optimize sequential memory access.
It's no good for random access. It's reported as "MSR MOD" by xmrig, need to run as admin.

Xmrig is smart enough to optimize the number of threads, are you sure you were using all 32?

The best performance is usually 1 thread for every 2MB of cache. This matches up with the number
of physical cores on most mainstream CPUs, meaning hyperthreading isn't necessary or helpful.

You know what, I realise I've made a big mistake  Roll Eyes.... I've confused the MSR Mod and huge page options! I'll edit my existing post and test with huge pages off tomorrow.

I'm definitely using all 32, same with my 3950x. As you suggest though, this isn't optimal for all CPUs, my 9900k performs better using 8 threads(as opposed to 16) preferably with affinity set to 1 per physical core.

It seems to be a Ryzen thing where performance is better with all threads used.

EDIT: Added some results to original results post.

Tuned RAM timings + huge pages OFF - MSR Mod On - 16,250 h/s

Tuned RAM timings + huge pages OFF - MSR Mod OFF - 10,750 h/s

Seems you are right, enabling huge pages is the biggest performance factor here. Then RAM timings, then MSR mod.


fyi, checked my friend's rig with 3900X and run using all 32 with huge pages ON (well, RAM timings is default) produce better performance than Tuned RAM timings first. i can verify that your approach enabling the huge pages made a better performance  Wink