Dual AMD EPYC Cpu not preforming in VRay

[seandunderdale]

Yeh, totally makes sense they wouldn't translate completely. All scenes are different and a cpu could excel at single threaded tasks over multi, but to be in the top 5 of all tests, and then to hear there is a problem with Vray + Epyc, sounds strange to me.

[^Lele^]

Yeh, totally makes sense they wouldn't translate completely. All scenes are different and a cpu could excel at single threaded tasks over multi, but to be in the top 5 of all tests, and then to hear there is a problem with Vray + Epyc, sounds strange to me.

This particular system has issues, and with the benchmark as well, so we can rule scene dependency out.
Clearly, those tested to be at the top of the benchmark list didn't have issues.

I wouldn't draw a general rule out of the one isolated case.

[rafrafa]

Still wondering if we should invest in Epyc vs Intel for our new render nodes. Last try was not convincing at all...
We have switched workstations to Threadripper (from dual Xeon) with huge benefits so I'm wondering if single Epyc CPU system perform well and multi CPU being the culprit... Anyone has a clue ?

[^Lele^]

It looks like memory access is often the bottleneck.
NUMA, f.e., will cripple performance.
I would assume multi-socket systems would not fare any better than single-socket of the same kind, and possibly worst.
I wonder if there's any commercial solution to properly using these many-core beasts, via for example VMs with cores and Ram cherry-picked for optimal perfomance (f.e. 8cores x 8 VMs).
Sure, one'd have less overall resources (i.e. RAM and Cores) but then perhaps a DR would work better, and so would using the machine as a whole farm with more than one jobs active on it.

I am merely guessing though, based on the fact that my single-chiplet, non-NUMA threadripper has none of those issues.

[rafrafa]

Yes someone in another thread suggest a VM approach I might try to test that as I own some mutli Epyc config. Could be interesting..