Hello,
I have a ATI HD6870 that is just fine, functionally. I'd say the only drawback is power consumption. My problem is AMD dropped support for it in their official driver. This really upsets me because they did this to me once before with the built-in graphics on my two year old laptop. This card is plenty fast, faster than some of the newer cards but they just decided they were not going to support it anymore. Well, I'm not going to support them anymore!
I'm not a gamer so I don't need the newest, fastest card, but I do use the OpenGL co-processing of the graphics card for photo processing in Darktable and any other program that can use it. The other reason I like to have dedicated card is more outputs and a little bit of horsepower for dual monitors etc. I don't mind buying a good used card and I'd like something at least as fast as what I have. I've been looking at GTX650 Ti. I know driver support can change overnight (boy do I know), and I've read about problems with the newer Nvidia drivers, but that's been quite awhile back. I'd like a card with the lowest power and cash requirements as possible but with enough horsepower to make it worth the cost. Ideally, it'd be nice to trade with someone wanting an ATI card but that just isn't going to happen. I'll just buy an Nvidia card and sell my ATI card.
The 6870 has 1GB DRAM and a 160 watt rating. I almost forgot. I don't mind an older card but I know the newer cards support more sync rates and resolution, so I really need some help here. A 2GB that's as fast as my 6870 with a 80-100 watt rating would be just what I'm looking for.