ASUS P7P55D and F3-12800CL9D-8GBRL

[YannLH]

I have the following setup:
Asus P7P55D, bios version : 2101
Intel e-750 (2.66Ghz)
F3-12800CL9D-8GBRL (4096MBx2)
Win7 64bits

I installed this dual channel ram as recommended in my Asus manual in slots A1 & B1. I have updated to the latest bios (2101) with default settings, then with DOCP then with XMP. The bios system information sometimes showed system memory usable size: 8192MB and sometimes 4096. Then in Windows, I had sometimes the 8GB, but when rebooting, only 4 were detected the next time. I also encountered several blue screens.
I also tried Windows memory check at startup and everything looked normal.


My current situation:
The DIMMS are installed in A1 and B1
Bios :XMP, 9-9-9-24, 1.5V for DRAM voltage, but only 4GB recognized...
In Windows, it shows 8GB installed but only 4GB usabled. As seen in the screenshots below.

It's getting me mad... I worked once or so I believed and then today only 4Gb are detected.

[Tradesman]

Pull both sticks and blow out the slots, make sure no dust/debris in there. Firmly insert the sticks , enough so that they latch into place on their own and see if that takes care of it (a number of mobos have very tight, sticky DRAM slots and that can cause the problem). If that doesn't help try running Memtest on each stick individually, (4-5 passes should suffice). If both test good then check DRAM voltage and possibly raise it + 0.06 and let us know how all goes.

[YannLH]

Ok, I'll try that.
In the meantime, I've taken pictures of my BIOS config so someone may discover one or two parameters that are incoherent.

I'll keep you posted
Cheers
Yann

[Tradesman]

Don't see anything jumping out, will get a closer look when I get back in a couple hours or so, in the meantime try raising the DRAM voltage as suggested

[YannLH]

Hey,

One of the DIMMS didn't work in any slot, so I brought it back to the store. They gave me the XL version in return, and it just worked fine so far.

Thanks for your help
Yann

[Tradesman]

Glad to be of help, don't often get a bad stick, but occasionally it happens. Happy it worked out OK, the XLs are great sticks and good OCer's was running a 2133/9 set in my Z77 at 2400