Windows 7 - x64 Win7 is reporting only 3GB out of 4GB RAM

I'm a bit confused why it's saying this. All the RAM is PC6400 and it's compatible with my machine.

I see this when I go to System properties (right-click Computer and properties). Beside the Installed Memory (RAM) label, it says 4.00 GB (3.00 GB usable).

Very strange. Hopefully it's just a tiny mistake?

What does it say in your Resource Monitor > Memory tab (the color picture). How large is the leftmost (gray) area.

This is normal. My soon to be upgraded HD 4200 has 512MB "dedicated" that I assigned to it in the BIOS. Now, with 4GB of RAM, I have 3.5GB usuable. Whs mentions the hardware reserved area, correctly.

I have 1025MB in hardware reserved. What exactly does this mean?

All the hardware you have has to be mapped into the 4GB address space (total RAM).

Is this something I have to check in my BIOS? I'm running an ASUS P5B-Deluxe. I wasn't aware that this MB or any of my other hardware needed any specially allocated RAM dedicated to it.

If the ram is "seen" in both BIOS and in Task manager and you are 64 bit, I suspect it is just caching 1 gig. frankly it should cache more and is perfectly normal.

Ken

It is not an address space problem since you are running x64. You have someone (most likely an on-board video) that uses real RAM at the tune of 1GB.

Its not the motherboard, its the hardware. Do you have an integrated GPU, any add-on cards? And is 7 x86-64 or x86? If its the second one, 7 can only access 3GB or so. If its 64-bit, it will depend on the hardware installed.

Ken, could you elaborate on this. I fail to see the caching effect.