A Messy Transition: Practical Problems With 32bit Addressing In Windows
 

Supreme Commander is extremely disappointing in how it handles running out of addressing space. Ideally we'd like for it not to crash, but realistically we'd settle for just an error message pointing out that it hit the 2GB barrier so that we could quickly reach a solution. Otherwise seemingly-random crashes tend to be one of the hardest problems to resolve as a user. Developers need to take care here to offer some kind of warning when the 2GB barrier is the problem; not everyone is or will be well read on the subject or have the time to diagnose it, when it's actually an easily solvable problem.

http://www.anandtech.com/showdoc.aspx?i=3034&p=1

Gamers are better off wait for 64bit Vista drivers and 4GB memory.

Supcom is not really GPU limited:)

If Supcom wasn't thrashing my 3.5GHz C2D rig like it was an old Pentium 4 box I bet it would be GPU limited. ;)

I had found MadBorris's forum thread regarding the 3GB switch and had already changed XP and modified Supcom with the /LARGEADDRESSAWARE flag several weeks ago... crashing has stopped, game plays fine, and I have not run into any instability with XP thankfully. In my opinion it was worth it, I can finally play 8 player games that don't crash 40 minutes in.