RAM not being detected


Feb 25, 2013
I just built a home made computer but not all of the RAM is being detected by my system. Can anyone help me to fix this please?

I should have 4x4GB sticks of Corsair Vengeance RAM installed.

I have an ASUS Rampage IV extreme motherboard which supports up to 32GB (8 slots). However my heatsink (Zalman CNPS12X) covers two of the RAM slots, so not all of the RAM sticks are in their recommended slots. Perhaps this is causing a problem? :??:

I also have Windows 7 Home Premium x64 installed which I believe should allow a maximum of 16GB to be used?

I used Belarc advisor and it shows the following (only detecting 4GB of memory): http://puu.sh/28dDZ

System Information also shows me as having 4GB of memory and then 8GB of virtual memory: http://puu.sh/28dxC

Yet when I use CPU-Z it is showing me as having 8GB

http://puu.sh/28dmw and http://puu.sh/28do1

In the BIOS, 8GB is being detected however the resource manager shows only 4GB ( http://puu.sh/28dpy )

Of course, there's still another 8GB missing even in the BIOS/CPU-Z screens. Crucial.com scanner also only detected 4GB.

Oh, and it's not being limited by msconfig: http://puu.sh/28dwf

So two questions, first of all how do I "activate" the 4GB that is kinda working, kinda not. And then, what do I do about the other 8GB of RAM?

I'm kinda stuck at this point.