Hey all. Thought i'd share my experiences with Diablo III, A Radeon 5670 512 DDR5, and a Dell 531 with an Athlon 64 x2 4000+ and 2GB DDR2 667.
After posting this thread, I decided to build a I3 system, but until then, i had a dell that was running Ubuntu that I was gonna try to upgrade and run games on, but i didn't have a copy of windows and of course that's what you need for most games, so i never did anything with it. but i found a copy of windows 7 that i had bought for another computer and installed it on the dell.
So then i read the best gaming card article and the card recommended for under $110 was the 6670, only because the 5670 had been discontinued. So i did a search and found one for about $50 so i jumped on it. I also bought 4Gbs (2x2) of ddr2 800 ram but it didnt work because it wasn't low voltage..
I installed the 5670 and it fit with maybe a millimeter of clearance. Seriously it was tight. Fired it up, it takes longer to boot like another member had mentioned when installing a graphics card, but it works like a charm. Diablo III runs great at 1080 on high settings. The only time it struggles is when you enter a different area, im sure the processor is too slow to keep up, but the graphics are smooth and i'm happy for now. but it has definitely fuel the fire for upgrades! when the ram didnt work, i bought a am2/am2+/am3 motherboard hoping it would work in that, but the order got cancelled and im glad because there no point in trying to speed up old technology...