T7810 dosen't boot when upgrading memory

Question

Hi,

I'm trying to upgrade RAM in my T7810, and pass to 8x32G.

When I start with just 4x 32G it doesn't boot.

I have 2x E5-2643 V4.

I plug RAM in DIMM 1 and 2 of each CPU.

I'm not getting amber led error about RAM, just a permanent white led with the sound of components working.

I tried resetting (CMOS battery, jumper, ...) but without success.

The RAM I'm using :M393A4K40BB1-CRC (RDIMM).

Bios updated (A34). I changed many times ... no luck.

Is there anyone to give help to get this machine boot?

Many thanks.

mazzinia_ · Answer

Hello, how much time are you waiting from boot, before powering down (due to the white led with nothing else) ? Because it will definitely retrain all the ram and can take a little time

Abidal · Answer

Hi @mazzinia_​ , I will say I was waiting for 15 or 20 min. Should I wait more? Thanks in advance.

Abidal · Answer

@mazzinia_​  Anyway, I let the machine on all the night. Tomorrow: no boot. :(

mazzinia_ · Answer

@Abidal​ no, should not take more than 30 minutes and that's with a lot of ram ( I think ). If you go back to the working configuration ( ram ) you had before buying the new modules, does it work ?

Abidal · Answer

Yes, it boots with old 16Gb sticks. I changed the CMOS cell also, no boot.

mazzinia_ · Answer

So, now has 4 x 16gb , and you got 8 x 32gb dimms.

Lets maybe find out if they are working ... it should work with just 1 dimm in the first slot of cpu0 (you can test this with your 16gb dimms) , so the thing would be checking if it boots with each one of the new dimms

Abidal · Answer

@mazzinia_​  I will try with one RAM. But as I saw in user manual, there is no config with 1x 16G per CPU. Anyway, I will give it a try and let you know. Thanks .

Abidal · Answer

@mazzinia_​  Hi, So, I trued : 1x8Gb in Dimm1/CPU1 - No RAM in DIMM1/CPU2 -> It boots 1x16Gb in Dimm1/CPU1  No RAM in DIMM1/CPU2 -> It boots 1x32Gb in Dimm1/CPU1  No RAM in DIMM1/CPU2 -> RAM error (Amber led) 1x32Gb in Dimm1/CPU1  1x32Gb in DIMM1/CPU2 -> No boot (Solid white led) I changed 16Gb RAM sticks , same result Any idea? Thanks.

Abidal · Answer

I have a T7810 with 8x16Gb RAM with 2xCPUs.

I want to pass to 8x32Gb RAM, but the machine wont boot once RAM plugged. It remain in solid white led, but no boot.

CPU: 5-2643 V4

RAM: M393A4K40BB1-CRC ( I tried also HMA84GR7AFR4N-UH)

Bios: A34.

Many thanks in advance.

Abidal · Answer

The RAM I'm using are all RDIMM, and all sticks are the same reference (M393A4K40BB1-CRC), so same rank (2Rx4), and same frequency (2400T). Bios is at its latest update (A34).  Thanks.

mazzinia_ · Answer

At this point we can say those 2 rdimm models are not accepted while posting ( SPD check ).

SNPCPC7GC/32G and SNP96JDYC/32G are officially supported , also Crucial Workstation Memory Kit (CT32G4RFD4240) (also server kits with also a dell label should be ok)

alanduken · Answer

That RAM is quad-rank RDIMM, which the T7810 with E5-2643 v4 CPUs does not support at that capacity. These CPUs and the T7810 typically require dual-rank RDIMMs and specific slot population order. Try using 16 GB or dual-rank 32 GB RDIMMs, and populate the white slots first per the Dell memory configuration guide.

Abidal · Answer

@alanduken​  Interesting! Is this limitation depends on T7810 itself, or the CPU? I mean, if I change CPU model, it will support quad RAM?

Precision Fixed Workstations

T7810 dosen't boot when upgrading memory

Was this post helpful?