Very funny... i am a Linux user and i use Sins on Linux... I have Win Xp pro x64 too but there, i am limited to 4 gb ram and only 1 core... using the game on Linux, i have game who have reach the 10 gb ram, something impossible on Win... i use a virtual processor ( 10 ghz ) to boost sins speed in place of 8 core at 2.66ghz where sins use only one of them...
More, i can on linux use my bios "discrete MTTR allocation" who work only for linux/unix system with more of 4 gb... it allow faster and better graphic effect... my driver is a nvidia one, one of the lastest version a dev version with cuda engine... ready to handle directx 11...
DirectX is not a problem for game on Linux... the big problem is the online gaming... at the begin, two problem was stopping us for online game... one is resolved, people are working on the second one... some other people are working on the impulse problem too...
About opengl... it is more used that some think... Only Windows and Xbox use DirectX... Linux, Mac OS, playstation 3, Wii, Nintendo DS, Playstation portable, Iphone, Android, Symbian Os and more use opengl...
One more advantage... using wine and playonlinux, i have several installation of sins... one for any upgrade, each with his own mod related to the sins version.... one click, i have the 1.05 with 7DS... a second click and i have the last version 1.12... both version can run in the same time, on the same desktop... try to make this on windows ( without using any virtual machine )...
Sound support problem... don't know them... my 7.1+2HD box work great... my supermicro install CD have linux, unix, solaris, mac, win, and vista driver...
For info, sins run ( not perfectly ) on openSolaris too... Some people have it running on Mac with OS X...