Some updates and positive news.
On our Dual EPYC node, we realised that 4 x 64Gb Dimm configuration was the issue. Supposedly on a Single CPU, filling 4 Dimm slots would enable the system to run in Quad Channel but since we have 2 CPU's then 4 Dimms is just a Dual Channel Memory set up and we would need 8 Dimms for Quad Channel or 16 Dimms for 8-Channel Memory set ups. (Our school boy error when setting out the original specifications).
So it seems Corona is much more bandwidth dependent on the number of memory channels much more so than Vray and Cinebench. When we ran benchmarks for Vray and Cinebench in Dual Channel, the scores were very good and matched to other systems of similar spec. It was only Corona that had issues, Dual Channel Ram literally halved the performance on the Corona Benchmark giving us around 20seconds where as Quad Channel gave a respectable 11 seconds. I suspect 8-Channel may push the Corona benchmark to 8-9 seconds but we don't have enough Ram to test this.
Other things we considered to resolve this speed issue before switch the RAM were:
- Upgrading to Windows Pro 11 Workstation Edition (This version can run more CPU's and RAM than Windows 11 Pro but it didn't affect our case even with 128 Cores and 256 Threads)
- Turning off Virtualization (Didnt really do much)
- Turning off VBS, Core Isolation and Memory Integrity on Windows (Didn't really do much)
- Power Plan on High Performance (Both in Windows and BIOS - Not sure how this affects the system performance as yet)
- NUMA settings on BIOS (Not yet looked into it)
- Windows Updates and latest BIOS
Hope this can help others out there configuring Dual Socket Systems. I would be interested to know from the Corona Development team why there is such a dramatic performance difference between DUAL and QUAD/8 Channel RAM configs as Vray doesn't have this issue at all.
Cheers.