Asus P5Q won't POST with RAM is some slots

[andrewkantor]

Hey, all -- got myself an Asus P5Q PRO with a Q6600 processor and a single 2GB DIMM of Muskin DDR2-8500 (1066 MHz) RAM.

I put the DIMM in the B1 (yellow) DIMM slot, per Asus's recommendation. All was well. I ran XP 32-bit just fine for weeks.

I decided to upgrade to 4GB of RAM and switch to Vista (also 32-bit). I bought an identical Mushkin 2-GB DIMM and put it in the A1 DIMM slot, figuring I'd also get dual-channel out of it.

But it won't POST. I tried various configs -- one DIMM or two -- and the only one that works is to have one or two DIMMs in the B slots (B1 and B2, yellow and black). If there's a DIMM in one of the A slots, the computer won't POST.

In other words, if anything's in an A slot, it won't post.

No overclocking here -- I reset my BIOS to default values. BIOS updated to Asus's version 14.

Any ideas what's going on? Is it a bad mobo? Am I missing a jumper that I need to set? Help! (And thanks!)

 

[KevinOC]

Have you checked the QVL list on the user guide yet? I was reading on that QVL list for your board, and i coudnt spot your memory.
Anyway, i will suggest you to RMA your board with ASUS based on your problem description. If B1 and B2 work for your RAM, then i am sure A1 and A2 would also work from my experience.
So my guess is that your A1 and A2 slots were not communicating with the northbridge of your board, therefore, you should consider to RMA your board. The 2nd option is to get a different pair RAM from the QVL and try it again in A1 and B2.

 

[andrewkantor]

Yeah, I noticed that my memory wasn't listed, but I trusted Newegg on that when I bought the board. And it has been working just fine... in those B slots.

I think you're right. I'll RMA the board, which is really annoying. But it does seem I've got a bad coupla DIMM slots. Thanks for your help!

 

[OVERKILL]

Fwiw,

My P5Q-Pro would not post until i 1st installed 1 stick of ram in the black slot, A1 i think.
I then went into BIOS and raised the Ram core to 1.98.
My pc then was able to post.
I then shut her down and installed my 2nd stick of ram in the A2 slot (2 x 2gb).

So far, it's working fine.