I have a Mac Pro 2.1 that I believe the video card may be faulty. What's the best way to test this? The video card is an ATI Radeon x1900 XT. I've read a few things online about this video card and its problems. The problem I'm having is that the machine comes on sometimes and others doesn't. The purpose of this post is to find the best way to test this card while in the Mac. I have little Mac knowledge so please keep this in mind when replying. Thanks in advance.