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Looking for dDR3 LRDIMM that actually works in R720XD

Dedicated Servers by HieuTce 4 replies 200 views
HieuTce

Member OP

#1

So I got this r720xd and I want to max it out with 768gb ram and I keep seeing conflicting info about lrdimm support and what actually works and I ordered some hynix hmt42gr7mfr4c-pb off ebay and they showed up and I populated all 24 slots and the idrac threw memory training errors and I spent like six hours reseating and swapping and it turns out those are qr dimms not lrdimms and the r720xd needs actual lrdimms for 32gb density and I am pulling my hair out because I want the 768gb config and I keep reading that you need 1.35v lrdimms and some people say samsung works and some say hynix and some say micron and I dont want to throw another 400 dollars at the wall and I am hoping someone here has actually done this successfully and can tell me the exact part number that posts and trains and shows up in idrac as 768gb because I am about to give up and just run 384gb which feels like a fail

KE

Member

#2

Less moving parts, less grief memory wants to be known before it is bought
Which part number found you, and which found the machine

wendy

Member

#3

The R720XD memory controller is picky but not mysterious. I have only pushed mine to 512GB with Windows Server 2022 Datacenter, and it was perfectly stable. Have you verified your BIOS and iDRAC are current? I have seen firmware resolve training issues that looked like hardware incompatibility.

Have you tried restarting it?
Carl

Member

Rack & Stack

#4

HieuTce said:
I want the 768gb config and I keep reading that you need 1.35v lrdimms

R720XD is Gen12, dual E5-2600 v1/v2. LRDIMM support is chipset-side, not Dell magic. You need PC3L-12800L or PC3L-14900L, 1.35V, quad-rank *logically* but LRDIMM buffer hides that from the controller. I have shipped pallets of these. Samsung M386B4G70DM0-YK04 works, Hynix HMT42GL7AMR4A-G7 works, both 32GB LRDIMM. Power draw at full pop is about 12W per DIMM, so budget 288W just for RAM. Your 1100W PSUs will handle it but check your 12V rail budget if you have 10-core CPUs and full PCIe.

visit twice: install and decom
all_rom

Member

Self-Host Or Die

#5

This is what you get for trusting cloud-era hardware instead of owning your stack properly. The real issue is laziness. If you were serious about privacy you would have bought bare boards and tested each DIMM individually before purchase. Convenience is the enemy. I run 1TB in a self-built Epyc board with no vendor lock-in and no iDRAC phoning home to Dell. Your R720XD is a surveillance node waiting to happen. Ditch it, build real, stop asking for handouts.

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