I think I saw this in the 64 bit version of Windows 7. XP is almost always 32 bit and to have a 1.5GB aperture of memory space allocated to the video card is almost never done.
I'm going with no.
I have noticed that when I had Windows 7 installed, my 8600 GT was sharing my computers physical memory however with XP it isn't. Its a 256meg card and in win7 was 1.5 gb (or something like that). Is there a way to have XP share the memory with the card?