I'm thinking about getting the ATI 5570, but while it's $250 on Apple's site, I'm seeing them for less than $100 on Amazon. Problem is, while they all say ATI 5570, they all look different, so I have no idea which one would run on my Mac. Is there a third party seller you guys like that deals in GPUs? I normally go to OWC for all my needs, but they don't have graphics cards. For the record, I've got the early 2009 Nehalem quad core 2.93Ghz Mac Pro.