My graphics card (ATI Radeon HD 2600XT) is on it's last leg and I need to replace it ASAP. Looking for recommendations. Do I need to look for something compatible with my OS (El Capitan)? MacPro - Early 2008 2x2.8 Ghz Quad-Core Xeon Intel Running OS 10.11.3 El Capitan UPDATE: Thank you all for your suggestions and comments, it has really given me a better understanding of the process. TheStork made a very good point... time and effort must be factored in to get the real cost of DIY. I am a busy parent with a home-based graphic design business (i.e. I don't work, I don't get paid) so I don't have a lot of spare time. Add in the fact that I am not a very technical person (this is my first foray into installing hardware) and the decision is pretty clear: I need to spend the extra cash to get a plug-and-play card that's for Mac. That said, what are your suggestions for a Mac-ready card?