pairing DDR3 in supermicro boards...

[eccerr0r]

I just found out my supermicro ddr3 motherboard enforces dual channel - if I have unpaired or incorrectly paired DIMMs in a bank, it will give up and start beeping... is this common on server boards?

I was trying a combination of two 4GiB modules and an unpaired 8GiB module. The only combo that worked is if I had both 4GiB modules installed. Having either size paired with an empty slot or dissimilar module, the machine would beep memory failure on power up. My other DDR3 boards would happily deal with mismatched modules though may not enable dual channel.

This is a microserver board, so it's using UDIMMs like consumer machines, though it does use parity for ECC.

As another thought I wonder what it will do with non ECC modules...would it also barf on them...

[Topcat]

Re: pairing DDR3 in supermicro boards...

What board? Some are worse than others....but as a rule, SM can be fickle about memory.

[stj]

Re: pairing DDR3 in supermicro boards...

something i learned about DDR3,
there are 2 voltages - 1.5v and 1.35v
the 1.35v are usually called "DDR3L"

dont accidentally use the wrong type or mix them!

[eccerr0r]

Re: pairing DDR3 in supermicro boards...

That's good to know, seems supermicro does sometimes enforce identical dimms in a channel to boot, which matches my suspicion. This kind of sucks, will have to dump this 8GiB DDR3 on another machine unless I find a matching module.

I think I have mixed DDR3 and DDR3L on a consumer machine, but this might not be acceptable on these server boards, will have to look at that. This is that Atom micro server board, and being Atom, perhaps those 4GiB were DDR3L, forgot ...

Hope I can either find another one or use this on a desktop board. My PVR which has way too much RAM (12GiB) for what it does already will probably get a memory upgrade to 16GiB, at least to see if this 8GiB module works or not ...

[eccerr0r]

Well, I finally found another 8G DDR3 ECC UDIMM (doesn't perfectly match) and swapped two of the 4G modules in the Supermicro board...

BEEP BEEP BEEP BEEP BEEP BEEEEEEEEEEEP -- No RAM found

WTF...or Oh No...

Hmm... then I noticed that I stuck the two 8G modules in different banks so the motherboard might have tried to pair an 8G with a 4G module. So I swapped the modules around so that the 8Gs are in the black sockets and 4Gs are in the blue sockets.

(waited for BIOS to boot, dang this board is slow booting...)

BEEP!

It boots and shows proper 24GB RAM! Memtest86 comes up fine. Slow... reports less than 5GB/sec with DDR3-1600 modules.

So yeah looks this SM board is really fickle about memory configuration.

The two displaced 4GB modules got dumped into my X58 board, now that's another problem I wonder about...