Hey Guys, All of a sudden only 8.0 gigabytes of my ram are showing up when I click on system properties or check the task manager. However, when I run Speccy or CPU-Z it still says I have 12 installed and shows all 4 slots properly being filled. I didn't see anything in the bios to address this, but the bios only sees 8 gigs as well. This is a dell XPS 8500. Any ideas? It was 12 gigabytes for the past 2 years and suddenly changed. It's as if Windows is ignoring 4 gigs. I have Windows 7 64 bit home premium edition.

You can memtest each stick individually to see if one has malfunctioned, also open the case and make sure they are seated properly.

http://www.memtest.org/

Yeah, probably something wrong with your RAM, Have you tried re'inserting them?

But yeah, you should have up to a maximum of 16 gigs I think, with the 64 bit version of 7 home premium, so it'sdeffinately odd.

And because you say all of a sudden I assume this is a new problem. My bet would be that it's hardware problems of some sort then, but I'm no expert.

> also open the case and make sure they are seated properly. <

That should you do !!!

Open your case and remove all memory sticks.

You have: 2x4GB & 2x2GB memory modules. So you have four of those.

Then insert, most preferable the two 4Gigs, in that way: http://oi58.tinypic.com/2wpuyl2.jpg

Check your BIOS. !!!

Swap the order of the memory, with all memory modules, to see if it's ram related or socket related. !!!

If you go into msconfig (Start Menu >> Search bar). In the boot, under Advanced Options, it there a maximum memory option set?

Also is Windows reporting 8.0GB or simply 8.0 usable (and 12.0GB installed)?

It could be timings issue. The memory controller is not detecting the memory timings properly, it could disable the memory module(s).