I've been researching for about a month now, and still don't feel comfortable about buying a video card. I bought a Mac Pro 3,1 and installed Sierra on it. It runs great. However, It has an ATI 2600 XT in it. I plan on doing video editing with this, and will need something better. From Windows, I've used AMD because OpenCL runs great with them. It seems Nvidia would be the easiest route to take since you can just download their drivers. I've read that the RX460 works out of the box and I've read that it no longer works OOB. I'm also tempted to just get a Flashed 7950 off eBay.. Having to see the boot screen isn't a big deal to me. Any help would be awesome.. Also, which ever card is recommended, what power adapters will I need to get? Thanks!