Hello, I would say mac the jump but know what you are getting yourself into.
First, and foremost, I have the XFX RX 480 8gb. It's fantastic. But, you cannot just install it directly from the box, you need to order a few extra cords. Those are called, mini 6 - pin to 6 - pin PCI cords. Amazon sells them, their from Jacob's parts or soemthing or rather. You need those because the ports on your motherboard suck. So, you plug the cord that comes with your graphics card into the graphics card, it should be a split cord that is dual 6 pin. Then you plug those new cords you just ordered the dual 6 pin (that game with the RX 480) and into the motherboard.
From there, you can now run the card but need to do all the kext stuff. That information can easily be found online and takes a few minutes. Once that's done, the card will play with zero issues. It does not have the boot screen. So, let me say that again just because. NO BOOT SCREEN. If you want to play games in Windows mode (such as I play Witcher 3 with everything on Ultra and it's fantastic) all you need to do is download a program (free) called BootChamp. That restarts your computer once into windows mode. Then when you shut it off or restart it from Windows it goes right back to your Mac. You can still boot into safety mode if ever needed. So, that's how you play games and again, Witcher 3. Ultra. Fantastic. All the games I've played are now working on Ultra. I don't play a ton of games on Mac as they just don't run as well. But, when I played Heroes of the Storm it was fine on Ultra but that's not exactly a world beating game.
There is a downside. That is that after the last update 10.12.3 I noticed flickers. When you start the computer there are flcikers that go across the screen. Typing this, and doing everything normally, nothing. It's fine. But, during the start when I am typing in my password there are flickers and when I use a program called Airdriod, same thing. But normally, nothing. I have also noticed when I click on the bottom to pull up my documents or downloads from the menu bar it's not fluid. It flickers and kind of *****. Whether that's the graphics card or the update, I don't know, but it wasn't like that before and it is now after the last update. It also gets wonky with youtube video's, but I assume it's the card, they still play fine and dandy, but if I expand them in Safari there's issues every so often. So, I exit and start it again and it plays no problem. So those are the side effects if any. Is is strange, yeah, is it a deal breaker. No.
Questions that I can answer.
1. No boot. Yes Recovery just restart and listen for chimes while holding the correct keys.
2. Don't know. I am running through a DVI cord.
3. It works. I talk about it a bunch above. But it works with zero problems.
4. I've had zero issues. No crashes or panics.
5. I play Witcher 3 at 1080 on Ultra. I think Civilization it'll easily handle as that's not a graphic intensive game. But there are tons of youtube video's with people playing it up to 4k. Watch those. I think it'll go Ultra on any available game at 1080. Hitting 1440 is where it gets wonky.
6. I was editing in Premier Pro CS 6 yesterday. I never timed it vs my 5770 but it worked wonderfully. When I had to toy with video it wasn't jumpy or anything before I encoded the video. At no point did I have to render anything in order to make it work. I dragged, clipped, added titles and exported it with zero problems. Better, don't know. But I had zero negatives from it.
7. If you have the GTX 980 I'd stay. It's more or less the same card with one exception. If Nvidia doesn't make you a driver next month and there's and update, tough cookies. If you accidentally update and haven't updated the Nvidia driver. Tough cookies. That could also happen with the RX 480, but it seems, at least from the outside looking in, that Apple plans on getting closer and closer with the AMD brand and pushing away from the Nvidia brand. I would have loved to get the GTX 1060 or GTX 1070 and not worried about it for years. But, that wasn't happening. And I wasn't about to pay $350 for a 2 or so year old card. So, I went with the RX 480 in hopes that the RX 500 (or 490) wouldn't be released and working directly from the box the following week. So far, everything I do has improved. If it weren't for the Documents and Downloads from the menu bar being screwy, and the flicker at the beginning I'd say there is nothing to complain about.
Either way, I like mine, I'm running a Mac Pro 4,1 that I updated the cpu and firmware of to mac it a 5,1. Thing is working wonderfully.
Hope that helps.
Derek
