THIS IS THE ANSWER The nvidia graphics card has a recall on it for Mac Pro model # MA610LL, late 2006 models. Sold as 2007 models from early 2007 to end of 2007. I have been fighting apple for years to have this recall fixed under extended out of warranty repair. Also, when it was covered. Apple, would not replace the defective graphics card. They, APPLE, finally agreeded to do a covered white glove inspection and repair. As should have been done, while it was under warranty. Instead, they replaced a failing optic drive, with a third party optic drive. They did not even address the graphics problem. I got it back, shipped via fed ex. In a wet, BUSTED open apple repair box, from the abuse in transit and drop on front covered brick porch. Fed ex label torn away address part left. No Apple security tape present. Signature required according to apple. Fed ex just left it. No invoice detailing repair, what they did. And computer password changed. Apple could not give me the password, that they swear they did...