BIOS and OS Do Not Recognize All Installed Memory

[munguin]

Hello, I'm new here.

Motherboard: ASUS P7P55D
Memory: G.Skill Trident 4GB (2 x 2GB) DDR3-2000 (F3-16000CL9D-4GBTD)
CPU: Intel i5 750 2.66 GHz

My problem is that neither the BIOS nor my OS (Windows 7 Ultimate 64-bit) recognize all 4GB that are installed. The BIOS shows 2096MB, and Win7 shows 4.00GB (1.99GB usable). I'm guessing the OS is saying 4GB due to the one stick the BIOS says is installed, plus the Page File, but I might be wrong.

At first, I thought it might be due to my OC settings, and I played with those a bit in the BIOS Setup, but even after just setting it back to the BIOS setup defaults, the amount of memory showing up still hasn't changed.

Today I tried installing just one stick at a time, first in the A1 slot, then in the B1 slot. The manual for this motherboard states that one DIMM may be installed as single-channel in either slot, yet neither stick worked in the B1 position on its own. Both worked fine in the A1 position. So my best guess now is that I have a bad motherboard--more specifically the B1 position.

I'm already looking for a new motherboard to buy, but before I do, I wanted to see if anyone else has any other ideas for me. I've researched this quite a bit, and after all the troubleshooting I could think of, I'm out of ideas.

Thanks for any and all help,
Mitch

[GSKILL TECH]

Make sure you CPU cooler is installed properly and not touching any part of the motherboard, but other than that, sounds like B1 is simply disabled.

Thank you
GSKILL SUPPORT

[munguin]

I have a ThermalTake SpinQ CPU Cooler, which is a beast and actually makes it impossible for me to put any memory sticks into the A2 position on this board, due to how close the CPU is located to the memory. But I can get sticks into A1 and B1 just fine. The SpinQ is very close to A1 however, and with the heatsinks on these memory sticks, it is possible that they're touching. Yet, that wouldn't really make any sense anyway, since the closest positions to the CPU are A2 and then A1. Everything works fine with a stick installed in just A1, even if the heatsink is touching the SpinQ. With a stick installed in just B1, and not touching anything, it doesn't work.

Still sounds like B1 is bad, it's just curious to me is all. I'll order a new motherboard today.

Thank you,
Mitch

[GSKILL TECH]

Not CPU cooler to memory heatsink, but CPU cooler to motherboard. It does sound like the slot is just defective though...

Thank you
GSKILL SUPPORT