I have a MacPro early 2008. 2 x 2.8 GHz Quad Core 16 GB RAM running up to date OS X Mountain Lion. I use a number of graphics, photo and movie apps which draw heavily on GPU power. Particularly PhotoShop CS 6 Extended and Da Vinci Resolve. I am currently testing a couple of new apps that make similar demands of the GPU. My machine is currently fitted with two paired NVIDIA GeForce 8800 GT 512MB video cards - each running one monitor - an Apple Cinema HD 2560 x 1600 primary graphics monitor and a secondary 3rd party 1920 x 1080 monitor which does not need to handle graphics (simply file handling etc.). At the time I acquired the machine these cards were the best available option. Now of course they are no longer adequate as demands increase for GPU power. In addition one of these two cards has just died and I am left with only one which is woefully inadequate. The MacPro itself is still a high enough specification to have plenty of life left if I can suitably update my graphics card. So my question is whether a high performance modern card is going to be compatible with an older early 2008 MacPro? Does anyone know of a good card with a reasonably powerful GPU that would be compatible? (preferably without totally breaking the bank). My next problem is that monitor 1 has a DVI connector and monitor 2 has a VGA connecter (that I use via a DVI adaptor). A modern card will probably have one DVI socket and one thunderbolt for the new generation of Apple displays. This is not necessarily a bad thing (indeed it may be preferable) as it is to some degree future proofed - but it does leave me with a problem as to how to connect my second monitor. Can I mix and match video cards in the same machine? In other words can move my NVIDIA GeForce to slot 2 to drive just the VGA monitor and install the new high spec card in slot 1 just to drive the primary graphics monitor? Is OS X clever enough to assign different drivers to different cards in different slots? Would this be more likely to work if the new high end card is also NVIDIA - would the new driver maybe be backwardly compatible with the old card? As you can see I am splashing around rather out of my depth here. Any advice, suggestions and clarification would be very welcome indeed preferably in simple English - I am not a techie. I am a creative. I do hope someone can help penetrate the mists for me ..