AMD EPYC Memory Population

[Erick]

I just want to verify that I have populated the memory in my Gigabyte MZ31-AR0 correctly. Here is a link to the quick reference.

http://download.gigabyte.us/FileList/Manual/server_qrg_mz31-ar0_e_v10.pdf

I have eight 16GB DDR4 (PC4-21300) RDIMM's, 2666 Speed, Dual Ranked memory. I have populated the following slots.

BankLabel Capacity DeviceLocator Tag
BANK 1 17179869184 DIMM_P0_A1 Physical Memory 1
BANK 1 17179869184 DIMM_P0_B1 Physical Memory 3
BANK 1 17179869184 DIMM_P0_C1 Physical Memory 5
BANK 1 17179869184 DIMM_P0_D1 Physical Memory 7
BANK 1 17179869184 DIMM_P0_E1 Physical Memory 9
BANK 1 17179869184 DIMM_P0_F1 Physical Memory 11
BANK 1 17179869184 DIMM_P0_G1 Physical Memory 13
BANK 1 17179869184 DIMM_P0_H1 Physical Memory 15

The bios is reporting 2400 speed, which is correct based on the documentation as I understand it. I just wanted to have another set of eyes on this to ensure I've populated the correct slots on this board.

Thanks!
Erick

 

[Patrick]

Looks right to me

 

[alex_stief]

would confirm, slot 1 seems to be correct for 1DPC.
Did you ever try to set memory frequency to DDR4-2666 manually?

 

[Erick]

Thanks for the confirmation. I can find in the bios where to set the speed manually, but it shows the top speed as 2400. I will have to take a closer look to see if it's possible.

 

[alex_stief]

In the bios of my board this can be found under "NB configuration"
Page 63 in the bios manual of your board:
http://download.gigabyte.eu/FileList/Manual/server_manual_bios_e_amd_epyc_10.pdf

 

[Patrick]

would confirm, slot 1 seems to be correct for 1DPC.
Did you ever try to set memory frequency to DDR4-2666 manually?

Yes. It was not a good idea.

 

[alex_stief]

What exactly do you mean?

 

[Patrick]

What exactly do you mean?

I killed two servers to the point of needing a full CMOS trying to run DDR4-2400 at DDR4-2666.

For those who think I am crazy, most Skylake-SP platforms will do this with a little BIOS work.

 

[alex_stief]

I see your point. If memory OC fails on Epyc, you either have to do a full CMOS reset or install memory that is actually rated for the speed you tried to set and then dial it back to compatible speeds. Pretty annoying and unnecessary.
I guess I should have mentioned that before poking Erick.