I have a 5770 PC version unflashed with 2 DVI ports and it works fine in my 1,1 and 3,1. You can pick them up for £30-35 on eBay. Not worth getting the Mac version as that's almost the same price as a GTX 680 PC version which is a better card and can be flashed by yourself easily (search this forum for info).
Got a refurbished ATI 2600 Graphics card on Ebay installed into 3.1 and problems went Bye bye! I'd like to thank all you who contributed here and helped me out with this issue. Thanks so much you guys RULE!