Windows 7 - Windows 7 64bit shows 3.73GB usable memory with 8GB installed

I have two sticks of 4gb PNY RAM (8gb total) installed in an Asrock A75M motherboard, which supports 16GB of RAM. I've already flashed my BIOS, thinking that may be it, but it didn't work.

Windows 7 as well as my BIOS show that 8GB of RAM is installed, but only 3.73 is usable. I have an onboard video card, so 256MB is dedicated to that, which makes sense, but why isn't the other 4GB showing up?

You need a setting in the BIOS called Memory Remapping.

There's no such setting in my BIOS.

The BIOS does report 8gb as well as Windows does, so wouldn't it be a Windows issue?

According to your mobo website and QVL......PNY is not supported. What speed is the PNY RAM you have? That could be part of your problem.

ASRock > Products > A75M > Memory Support List

It's running at 1600, auto set it to 1066.

Neither setting worked

If you run resmon and look at the memory tab, is the missing memory "Hardware Reserved"?

4375 MB shows up as "Hardware reserved".

Thus you need Memory Remapping in the BIOS.

Good explanation here: The system memory that is reported in the System Information dialog box in Windows Vista is less than you expect if 4 GB of RAM is installed

I have a similar, those not as drastic, problem with my Dell Precision 370 with 4GB of ram. 1GB is hardware reserved and the BIOS does not support Memory Remapping.

I had the same problem, with the same board. Make sure your ram sticks are installed in the correct slots. If you have only 2 sticks, make sure they are both in BLUE or WHITE, not BLUE AND WHITE. I had 4 GB installed in 1 BLUE and 4GB installed 1 WHITE and it gave me the same memory readings. When I switched them to both BLUE slots, I got the full 8GB minus what I have in reserve for the video card.