Gigabyte MZ31-AR0: EPYC Motherboard With Dual 10Gb/s LAN, 16 SATA Ports, Seven PCI-E Slots

[ddriver]

Yes, you don't have to use all the channels available on any motherboard.

However, unlike most consumer boards, you will be directly starving a de facto CPU from memory bandwidth, forcing it tho share it with another CPU.

Note the subtle difference between channels and slots in the context of MCM package solutions.

And the subtle difference between utilizing 100, 50 or 0% of the available memory bandwidth per CPU.

[malakudi]

Quad channel memory bandwidth is more than enough for most workloads. While it is good to have the option for 8-channel memory bandwidth, I would prefer buying 4*16 DIMMs instead of 8*8. Than way I have an upgrade path by just adding 4*16 DIMMs later. Can Michael test the system with just 4 DIMMs to see the performance? Also, is it possible to run on 2-channel only too?

[coder]

Quad channel memory bandwidth is more than enough for most workloads. While it is good to have the option for 8-channel memory bandwidth, I would prefer buying 4*16 DIMMs instead of 8*8. Than way I have an upgrade path by just adding 4*16 DIMMs later. Can Michael test the system with just 4 DIMMs to see the performance? Also, is it possible to run on 2-channel only too?

EPYC is NUMA, so watch out for that. Only pairs of the channels are interleaved - not all 8.

And IIRC there was some one posting EPYC or ThreadRipper benchmarks on the Phoronix news feed with silly memory configurations like 1 and 2 channels, earlier this year. Search for it.

Edit: this article references his earlier 1- & 2-channel tests with ThreadRipper, but I didn't find those articles. Didn't look very hard, though.

https://www.phoronix.com/scan.php?pa...eadripper-DIMM