need help finding a compatible pci sound card for audio production

[nunrg2009]

I've noticed some people on here are doing audio production with their hack macs... I've been using reason for years but recently I've been doing some stuff with ableton and reason in rewire slave mode. I'm also running trilogy and absynth and some other AU's and it's putting a beating on my processor. My onboard HDA is doing okay but I'd like to get a pci (or usb if that is my only option) sound card with some kind of hardware acceleration because overlapping notes from multiple AU's are sucking up tons of processor power. Honestly I'm new to running multiple production programs at once and I don't even know if a new card would help. Maybe I just need a better processor

I found an M-Audio 7.1 card that is supposed to be pc and mac compatible but the reviews say otherwise, supposedly there are no drivers for anything above tiger 10.4.6