Modo, my primary modeling tool, uses advanced OpenGL and it sings with my SLI card. I can turn off one of the cards (via the properties ... the 9800 GXT is really just two cards in one) and the hit my system takes in a 3D app is visible. I can also run DirectX apps with no problems. For example, I can run UT3 at the highest settings, full screen (my 24" monitor's resolution is 1920 x 1200) and the game is absolutely fluid.

Sounds great. How about noise? Did you do something to reduce the noise level?

i have just found out that 32bit applications can be compiled with the LAA option (large address aware). then they can use up to 4gb but they don't have the increased memory usage of 64bit applications. blender has LAA builds and probably some other 3d tools use it too. so if you use a 64bit windows and only have 4gb ram you probably get the most out of it with LAA.

Frank: I'm sorry but I cannot tell as I have never used the 64bit version of Windows XP.
However I'm considering buying it just to have an option to not use vista when I'm going for a new computer with more than 3GB someday.

However I did a quick google search and found this article (more than 3 years old) about WinXP Pro 64:
http://www.zdnet.de/enterprise/os/0,39023494,39132549,00.htm

Here is another article (also 3 years old):
http://www.pcwelt.de/start/software_os/w..._moeglich_sein/