This is actually some of a linux question

[albator]

http://springrts.com/phpbb/viewtopic.php?f=10&t=28642

[gajop]

i use nvidia 8800 GT (same as 9800 GT) and it's good enough;
don't use compiz nor ubuntu, nor gnome, since it gets in the way so can't say how that'd work for you - probably fine anyhow