Dont worry about it, just read my post edit.

Could you give a link for that?

I just searched google for XP's max ram and XP 32 ram limit. I took the most stated number of what random tech forums were saying. There was even some 3GBs thrown out on some sites which I know is wrong. I also remember learning somewhere that 3.5 was the visible limit. It will read up to 4GB without showing it after that it jsut wont read any.

http://forums.whirlpool.net.au/forum-replies-archive.cfm/751325.html here is one

That says what I have been thinking all along. 32-bit OS will address a full 4GB of physical memory including other memory you have in your PC besides RAM. So I start with 4GB, minus the 512MB from the Video card, and then say minus another 512MB for the rest of the stuff. That leaves the OS able to recognize 3GB of RAM but that doesn't happen and I don't know what is taking up another 512MB of memory.

wondering, how much Virutalized video ram is your drivers using I wonder (Nvidia's drivers might report it.. maybe). I have a 4850 512mb, but I can use 768MB of vram due to virtualization.. however I do run vista it might be apart of WDM and not apart of XP (profile has my full system settings).

could you also go into device manager, find your video card. right click goto properties.. in the tabs goto resources, then write in here all of the Memory Ranges. I just want to add those up.

I'm also gonna dig over your mobo's manual a little more now that I'm home from work, see if there is anything else that might possibly be doing it.

hmmm there isn't much here that could be stopping it.. the only other thign in the bios I can see that could be doing it is

"Init Display First"

by default its set to PCI.. setting it to PEG _might_ stop it from trying to use the onboard for detection since it'll succeed with the PCI-E card.. but I am clutching onto straws here (ie I'm doubtful that'l change anything). is the Bios actually reporting 4GB of ram too? not sure if you've answered that yet, if its not 4096MB then we have issues with ram.

I'd really love to dig around your device manager right about now.. *preps plane ticket*

I was using the 3rd post in that link actually. But I explained it above. And I found my old PC tech manual which states what I said above.

As some people have already noted, Windows cannot and does not provide all 4GB of memory address space to an application. Each application is *only* assured 2GB of contiguous memory space by the 32-bit Windows kernel. Further memory allocations must fit into the artificial boundaries that the kernel has imposed on the memory space. So, if you write an application that allocates a 3GB block all at once it will fail immediately. It is not uncommon at all to see a normal application fail at around 2.2GB or so working set size.

For those of you who like pictures, this is roughly what's happening, X's are space that the OS has reserved for itself, as the application grows it has to fit any new memory allocations into smaller and smaller spaces:

0GB                                     2GB                            4GB

|<---Application Memory -->|X|     |XX|   |X|     |XX|   |

Check your pagefile settings, make sure they are set to a reasonable value: 1.5x your physical memory should be right for a standard machine. If you like to live life on the edge, you can always enable the /3GB switch in your boot.ini. I do not recommend doing so as it does not play very nice with your average application/driver.

You could also upgrade to a 64-bit OS. All this said, think deeply about whether you really want or need the extra memory. Windows 64-bit versions are still young and have plenty of bugs, driver support issues, and general annoyances to make your life hell.