I have an X-fi xtreme gamer... You're probably better off without it. Microsoft dealt creative a death blow by killing EAX in Vista and 7. You can beat yourself up trying to get some older games to use EAX with Alchemy, but it's just not worth it. Newer games don't use EAX, you don't need a Creative card. Onboard or another brand is fine, and probably has better drivers.
My new laptop (Asus G72GX) has Realtek HD audio, but Creative EAX software installed from the factory. I was getting total system freeze ups every few minutes. Uninstalled the Creative software, fixed. I tried reinstalling it, and I got lock ups again. Then I uninstalled the Realtek HD audio, and the sound was ok, but the Creative software said there was no supported devices installed for EAX and virtualization. THEN I installed the Realtek HD drivers again, and now it all plays nice together. But what does the Creative software really do for me? Nothing.