Noob problem with pc reading memory.


May 16, 2009
Hi all,

I have a dell xps 600 with 1 GB of RAM that came with it in the form of 2 512 sticks. I recently bought 2 sticks of 1 GB and installed it, but the when windows loads, it only detects the 2 GB sticks.

When I check the bios, it detects all 3 GBs of memory. I have had a similiar problem with another pc, and it was solved by simply changing out the newly installed sticks with some of the same kind from the same manufacturer with a slightly different hardware design.

I was wondering what might cause this problem? I can't find anything anywhere.

btw, I am using the right kind of memory and it is installed correctly so it's not a problem that's completely obvious.

Thank you all for your help!


Jul 16, 2008
Have you tried switching the slots that the RAM are in? If the 512s are in slot 0,2 and 1gb in 1,3 try reversing that so the big sticks are 0,2.

Use cpuz id to check the RAM from within windows.


Jul 18, 2009
This thread is old, so the OP probably found this out already or gave up. But it's good info on the XPS 600 that took me forever to discover and verify, and I saw tons of replies on various hardware sites about this same issue that were understandably going off in dead-end directions.

I'm an IT Pro myself, and knew at the time I bought my XPS 600 3+ years ago that I shouldn't buy any proprietary PC. But I got a great deal on it at the time, so I did it anyway. So 6 months ago I want to upgrade my RAM, and I run into this same issue and it drove me crazy - up until the point it made me mad as hell!

I could only get 2 GB to be recognized by Windows XP. I troubleshot and troubleshot, and verified that all of my RAM sticks were fine. So were the DIMM slots and mobo itself. The BIOS saw all of my memory fine, no matter what combination of sticks and total RAM I tried up to 8 GB. (I had access to multiple sticks of 512, 1 GB, and 2 GB, etc.)

I'll skip most of the inevitably maddening details of dealing with Dell End-user Tech Support ala India, but in the end I found out a small but crucial detail. The mobo/chipset in the XPS 600 can't see more than 2 GB of RAM if you are running a 32-bit OS.

At first, Dell even tried to tell me that no 32-bit OS could see more than 2 GB of RAM, but since I knew that was complete BS, I pressed them on it, and finally got escalated to a tech who related this bad news to me. I guess the geniuses at Dell/Nvidia/Intel at the time didn't think anyone would need more than 2 GB of RAM on this machine in 32-bit XP? (Hm, reminds me of the Bill Gates quote saying 640k should be enough for anybody.) Then they went on to tell me that even though the OS wouldn't see more than 2 GB, if you had say 4 GB installed, the chipset would supposedly make some of that extra RAM available directly to your hardware devices like your video card, so your performance would still be better with > 2 GB of RAM. I even wanted to believe it, but. . . I think I need to call BS on that one too.

So, on the XPS 600, if you are running a 32-bit OS, you are capped at 2 GB, rather than the 3-3.5 GB you should be able to see in a 32-bit OS with 4+ GB installed. If you want more RAM, you need to install a 64-bit OS, in which case you can put in up to 8 GB.

Quote from's memory selector tool after running a system scan on the XPS 600, just for kicks:

"Maximum memory depends on the installed operating system. 8GB maximum for Windows XP 64bit based systems and 2GB for Windows XP 32bit based systems.Installed in pairs of modules."