Thinking about buying a 3.2GHz Quad 5,1 to replace my 2.8GHz Quad 3,1 on eBay for a really good price. * The geek bench scores between them both are significantly higher on the quad 5,1. In basic real-world tasks, is there going to be a perceivable difference? * I notice that the 5,1 quads run at 1066Mhz instead of 1333Mhz for the ram speed. I assume that dropping a 3.33GHz or a 3.42Ghz will change the ram speed to 1333MHz, if the ram is 1333MHz? * I do enjoy gaming. I had my mind set on aa 680 GTX, but I'm willing to entertain other options. I'm looking for a no-frills GPU with boot-screen and all that "just works" with a limit of $200. * Part of this is inspired because my girlfriend wants my 3,1, so I'm "in need" to update to something better and would still like a tower. Need something to tide me over until the new Mac Pros come along. The seller is also selling a 2.66GHz Quad for $50 less. I assume if i'm going to upgrade to a 3.33GHz Hex, I should go for the 2.66GHz model and pocket the change... How can I assume that either of his models are true 5,1's? Is there a build date on the back of the Mac Pro?