RAM not showing

[addamski]

Hello,
I have built a workstation spec;
Supermicro X8DAI mobo
2x Xeon X5660
Win7 Pro 64bit
I have installed 24GB (1333mhz)
RAM = 3 x 4GB modules per CPU.
Windows only shows 20GB and Bios shows a fraction over 20GB but not the 24GB I have installed.

Does anyone know why this is?

Thanks

Adam

 

[AdrianPerry]

Well your CPU/OS/Motherboard certainly aren't limiting factors.

At a guess id say you either have a faulty RAM module, or a faulty RAM bank on your motherboard. Id suggest trying 1-2 sticks at a time and test they all work, following that you'll either find a faulty one, or if they all work you can presume one of the banks is faulty. Test the RAM in some different banks on the motherboard and see if you can narrow down the fault that way.

 

[addamski]

Thanks for replying,

Ok it looks like its not the RAM modules now. I swapped them about and one of the DIMM slots seems to not recognize the module.
I swapped the CPU's over to see if there was a problem with the controller in one of them. Same DIMM slot on same bank for CPU2 still.
This sounds like a motherboard problem now?
Before I send it back, is there anything else I should try before hand.
If they test it and find no problem I will get charged so need to make double sure its the mobo that's the problem?

Thanks

Ad

 

[AdrianPerry]

Yes almost certainly a motherboard problem if neither CPU nor any other RAM modules worked in that slot. There's nothing else it could be as far as I am aware.

Not sure if you can check in the BIOS which RAM slots are being used and which aren't? Might show as a "dead slot" or "blank slot" or something like that even with a RAM module installed? <-- Just an idea, not sure if its possible since I've never needed to

 

[addamski]

Hello,

Right, its still showing up with only 20 out of the 24gb installed.
I sent the motherboard back and it was tested with 2 banks of 3 x 4gb modules and they said it was fine.
It showed 24gb.
I got it back today and re-tested the RAM and that all works so I am at a complete loss now

Bios says nothing about RAM other than the bus speed etc. No indication of slots.