2 OCed 5850s should be pretty darn good for a good while. You can actually flash the BIOS and do voltage tweaking on many of them, but I don't have one an haven't done it, so I don't know which ones work best for that. Probably easiest with the ASUS since you don't have to worry about voiding the warranty by flashing, plus they generally have solid cooling. Whatever the case, the Sapphire cards generally have pretty good cooling, so that might help your OCing, also- XFX has the double lifetime warranty in North America, so if you live in the US or Canada, that'll be good for you too. some of the MSI boards have the extra OCing features as well- good cooling and I think voltage tweaking.