Missing RAM in Windows 7

MojoPin · 5 Mar 2011 at 11:25

Hello
I've recently built a new PC, installing 8gb (2x4) Corsair RAM (http://bit.ly/g1pj3L) into a Gigabyte P55-UD5 motherboard.
The BIOS says there is 8gb, and in Device Manager 8gb is detected, but it says "(3.99gb usable)" next to the total.

I've installed and reinstalled Windows 7 64-bit three times now, updated BIOS, and drivers too. Common solution is to untick a box in MsConfig too, but this is unchecked on my system.

What can I do to get all 8gb working? Any ideas please?

Thanks in advance.
Andy

mukhs11 · 7 Mar 2011 at 14:27

do memtest as one of the sticks could be faulty

EGuitarStar · 7 Mar 2011 at 14:53

Double check you have actually installed the 64 bit version of Win 7, go into msconfig --> Boot Tab --> Advanced and then set the maximum memory to 8GB.

If that doesn't work, memtest.

hyperst · 7 Mar 2011 at 17:11

I had an issue that if i raise my base clock on my cpu past 187, I get 1.99gb usable, keep it at 187 and I have access to all 4gb, are you doing any overclocking

hawker1986 · 7 Mar 2011 at 17:26

Failing all else reseat the memory and CPU, I lost a stick cos of some dust in the CPU socket, miraculously reappeared after i got rid of it.

Hawker

MojoPin · 7 Mar 2011 at 18:47

Thanks for your replies.
@muksh11
@EGuitarStar - Definitely is the 64bit version
@hyperst I have slightly over-clocked, but the problem was there even when the processor was out of the box.
@hawker1986 I have a terrible feeling you're right!

The thing that puzzles me most is that Windows and the BIOS detect how much RAM there is, 8gb, but that only 3.99gb is usable. Surely if it was faulty or connected improperly, the system wouldn't be able to detect both sticks?

hyperst · 7 Mar 2011 at 19:00

I would say it is a BIOS setting, do you have a memory remap option or some strange setting in the BIOS somewhere

MojoPin · 7 Mar 2011 at 19:05

There are several options, the main one being to install an XMP profile. Without this enabled, the memory runs at a much lower speed. Enabled, and it runs at 2000Mhz.

What is memory remap? (thanks, by the way)