Steve_MND

Easier said than done, unfortunately. According to the Nvidia's driver download webpage, they apparently "do not support the Macintosh operating system at this time," despite having built the Nvidia 8800 GT card that's in many of the Mac Pros (like the OP's and mine).

I have no idea how that is supposed to make sense, but there ya go.

Well, that's a bit depressing. I figured they'd send out some sort of initial general email when they were getting ready to solicit applications for the Mac Beta, but I guess neither of my email addresses were among those randomly picked for the first two waves. And here I was, eagerly checking the Transgaming site's breaking news every couple of days for an announcement along those lines, and apparently it's been underway for a whole month now. :-(