Ram for 7003 Epyc

[Sestemybe]

I am assembling a new server and going with the AMD Epyc platform. So far I have purchased a H12SSL-I motherboard and a 7713 processor. I need to purchase 8 sticks of ram, I want to get 64GB sticks for 512GB total. I have read the release papers and it shows the processor as being compatible with most ram.

However I have read some posts stating that Epyc doesn’t like Hynix, LRDIMM, or 4Rx4 modules. I have also read about people saying they work fine. Most of the cheaper 64GB sticks I’m finding are Hynix or 4Rx4 modules for $100-$120 a stick. I’d like to not spend $200+ a stick if I can help it.

So what’s the scoop with Epyc and ram? I haven’t been able to really locate any definitive data one way or the other on this. Any help or advice is sincerely appreciated.

 

[RolloZ170]

However I have read some posts stating that Epyc doesn’t like Hynix, LRDIMM, or 4Rx4 modules. I have also read about people saying they work fine.

depends on the gen (7002 or 7003) and the condition of the LRDIMMs.
if you get new ones you will be fine. outworn 2400 ones can having issues.
note 4R RDIMMs are not supported(rare available)

https://www.amd.com/system/files/TechDocs/56873_0.80_PUB.pdf

 

[Sestemybe]

I have a 7713 processor ordered for the motherboard. Do the 7003 processors give more options? Some of the posts I read were leading me to believe some ram that AMD says is compatible isn’t.

 

[RolloZ170]

Some of the posts I read were leading me to believe some ram that AMD says is compatible isn’t.

if the long used RAM does not work with the spec.timings given in the SPD you run into issues. LRDIMM especialy HYnix 2400 and under have no headroom in latency.
if yo buy brand new RAM you are fine. very long used LRDIMM is a lottery.

 

[Sestemybe]

If I purchase 2666 or above the issues are less?

 

[RolloZ170]

If I purchase 2666 or above the issues are less?

sorry:
after reading all threads about H12SSL & 7002/7003 i can not recommend buying LRDIMM if you want to be on the safe side.
it is very strange supermicro does not list any LRDIMM as compatible.

 

[Sestemybe]

sorry:
after reading all threads about H12SSL & 7003 i can not recommend buying LRDIMM if you want to be on the safe side.
it is very strange supermicro does not list any LRDIMM as compatible.

That’s what I’m trying to get to the bottom of. AMD lists many types of compatible ram, that users here occasionally list as not being usable, while other users say it is. AMD lists it being compatable with up to 2TB of ram, which requires LRDIMM.

 

[drdepasquale]

I can confirm Hynix RAM works fine with AMD EPYC processors. I use 3200 MHz RDIMM modules in my workstation.

 

[RolloZ170]

@drdepasquale
yes RDIMM is not the problem here, we are on Hynix LRDIMM & supermicro h12ssl.

 

[RolloZ170]

That’s what I’m trying to get to the bottom of. AMD lists many types of compatible ram

i got about 30 Hynix 64GB DDR4-2400 LRDIMM as untested few years ago.
i have only a supermicro x11 system to test each LRDIMM.
Hynix provides working timing/latency parameters in the SPD of the LRDIMM modules. they are very agressive.
we have seen same memory(same CPUs) gives better banwidth in supermicro than Dell.
it turned out supermicro used this SPD timings closer. i got half of the modules only working @2133, other latency increase should solve this too but i could not change these in BIOS.
if supermicro h12 boards DON'T completely unsupport LRDIMM, you can get them working by manualy adjusting some timing paramters if provided in BIOS/UEFI.
someone should ASK supermicro if LRDIMM is supported by H12 SP3 or not.

 

[drdepasquale]

LRDIMM is supported according to the manuals for the H12 boards. Though given that these manuals have some mistakes it's best to ask Supermicro

 

[RolloZ170]

--

LRDIMM is supported according to the manuals for the H12 boards.

but i recommend to stay away from old used HYnix 64GB DDR4-2133/2400 LRDIMM, they have known issues on other platforms(Dell intel-EX)

 

[drdepasquale]

--

but i recommend to stay away from old used HYnix 64GB DDR4-2133/2400 LRDIMM, they have known issues on other platforms(Dell intel-EX)

I use that memory in my older system with the Supermicro X10DAC motherboard, it seems to work fine. I tried putting it in the new EPYC board and it didn't work so I had to buy new 3200 MHz RDIMM memory

 

[RolloZ170]

if on consumer desktop boards a specific stick not work, there will be a BIOS update with "improved DDR4 compatibility"
its mostly not more, but no one does it.

 

[klove007]

I am experiencing issues with the cheaper Hynix 64gb 4rx4 DDR4-2400 modules found on eBay with a SM H12HSI-N6 and two 7542's board install this week. I am trying to update bios to 2.4 and see if I can flush out a fix for these issues over the next couple of days.

 

[Spartus]

These work FYI:
M393AAG40M32-CAE
128GB RDIMM 3200 4Rx4
(3DS 2H 8G x 4) x 36

Both supermicro and gigabyte boards. Not relevant to "cheap ram discussion", but just in terms of broad compatibility and ranks.

 

[klove007]

These work FYI:
M393AAG40M32-CAE
128GB RDIMM 3200 4Rx4
(3DS 2H 8G x 4) x 36

Both supermicro and gigabyte boards. Not relevant to "cheap ram discussion", but just in terms of broad compatibility and ranks.

Very nice dimms, unfortunately 2x my budget.

 

[Damo]

Is this an H12SSL issue or EPYC 7003? Because I am having trouble with SAMSUNG 64GB PC4-2400T-L ECC 4DRX4 LRDIMM M386A8K40BM1-CRC5Q. Sometimes it boots, sometimes it shows 'ad' in post snoop, has about a 50% chance of booting.

 

[RolloZ170]

Is this an H12SSL issue or EPYC 7003?

H12 does not like LRDIMMs. swap them to a gigabyte and they work fine.

 

[RolloZ170]

Because I am having trouble with SAMSUNG 64GB PC4-2400T-L ECC 4DRX4 LRDIMM M386A8K40BM1-CRC5Q. Sometimes it boots, sometimes it shows 'ad' in post snoop, has about a 50% chance of booting

i doubt this is a LRDIMM issue.