Interesting update to this thread. I've been using the very same setup that I provided the above instructions, going on about a month and a half now. What I've found is that if I leave the Crossfire connection cables attached to the graphics cards, while booting into the Apple OS X environment, startup performance is significantly reduced. It seems to take upwards of about 3-5 minutes before everything settles. This is a bit of convenience problem because the SLI support in Windows 7 by dual booting with Boot Camp is superb. Games and programs are buttery smooth. While in the OS X environment, you cannot use SLI but the second graphics card is recognized and utilized by rendering apps. The best thing then appears to be manually connecting/disconnecting, when you are booting into the Win7 or OS X environment.