Hi I'm just looking for something cheap and used in the $50 range that will support Yosemite/El Capitan/Sierra. I see that people like the mac version of the ATI Radeon 5770 HD but those are still going for $200 ebay. Anything else out there that is decent? What about the NVIDIA GeForce GTX570 HD. I'm not looking to play games or anything. Thanks for your help.