Ok,,, there are hundreds of various GPU's out there... what is best means to compare what are best options per $$$ [value] for either comparing when acquiring in a refurbed MacPro or to buy for an upgrade. Have seen / read sites such as: http://www.gpureview.com/show_cards.php?card1=615&card2=617 and http://www.techarp.com/showarticle.aspx?artno=88 But not quite sure what aspects / components are actually the most critical, esp. in regards to digital images [ie: PhotoShop, Lightroom, Aperture, etc.], games, and video editing. For example, when comparing two refurbs from Apple store, there are these two options: $2039 One 2.66GHz Quad-Core Intel Xeon "Nehalem" processor 3GB (3 x 1GB) of 1066MHz DDR3 ECC memory 640GB Serial ATA 3Gb/s 7200 rpm 18x SuperDrive (DVD±R DL/DVD±RW/CD-RW) NVIDIA GeForce GT 120 with 512MB GDDR3 memory vs. $2119 One 2.8GHz Quad-Core Intel Xeon "Nehalem" processor 3GB (3 x 1GB) of 1066MHz DDR3 ECC memory 1TB Serial ATA 7200 rpm 18x SuperDrive (DVD±R DL/DVD±RW/CD-RW) ATI Radeon HD 5770 with 1GB GDDR5 memory To my naive eyes, seems from what I've read about these two cards, the ATI here is quite a bit faster / better than the GeForce version... and therefore makes the ~80 dollar difference very positive to go for the 2.8GHz machine, esp. given its larger HD, faster processor, etc. But mainly question here in this thread is how to determine which GPU is "best",,, and to compare it per specific needs to others? Thanks.