HELP! - 6GB installed, showing 2GB usable?

[Galwynd]

Hey everyone!

Upgrading a Dell XPS600 to 6GB of DDR2 memory, and under installed memory it shows:

Installed Memory: 6.00 GB RAM (2.00 GB usable)

What the heck is going on here? I'm running 64-bit Windows 7 Professional

The motherboard maxes out at 8GB (per the users manual)

Any ideas?

 

[jaquith]

Incompatible RAM: {the BIOS sees two different incompatible sets and turns-off one set; protection from fault/errors}
Clearly, you're mix-matching RAM {4 DIMM -> 2X2GB + 2X1GB}. The RAM needs to have the SAME: Speed, CAS timings, Voltage, and Type {chips/side and in some BIOS cases same size}. I know Dell often bastardizes their RAM to allow different sizes.

For now, refer to the manual's placement of RAM and remove the 2X1GB and try the 2X2GB.

Please list the EXACT RAM - provide a link to both sets. You can use CPUz to identify {SPD tab} -> http://www.cpuid.com/softwares/cpu-z.html