Upgrading GPU, i5-3570k, 8GB RAM, SSD, 650W psu

An MSI GTX 980 Ti Twin Frozr V 6 GB GPU will be perfect for your needs if you can find one in stock.

Witcher 3, 1080p, everything on including Hairworks, 50-60fps, no SLI? Not going to happen. Doubly so with Hairworks on.

You say you've read through the benchmarks, but I've not a single benchmark where even a GTX980 can hit 60 fps average at ultra without Hairworks, and Hairworks delivers a heavy performance hit (~20%) on nVidia (that becomes massive on AMD).

One set of benchmarks - 1080p/ultra/no Hairworks, GTX980 gives 28 fps min, 56 fps average.
Another set - same settings, GTX980 gives 46 fps min, 49 fps average.
Another set - same settings, GTX980 gives 60 fps average but with drops into the teens that they describe as "jarring".
Some 980Ti benchmarks] - 56 fps average @1080p/ultra, 46 fps minimum.

The best you can do right now for Witcher 3 1080p/ultra is a GTX980Ti and living with ~40-60 fps and no Hairworks. In short, for what you want you'll have to wait a year or two. Or wait to see if they optimise the game much.

AMD doesn't need Hairworks. AMD has a great implementation of tessellation, which works just fine in Witcher 3.

http://wccftech.com/witcher-3-run-hairworks-amd-gpus-crippling-performance/
http://wccftech.com/amd-announces-witcher-3-hairworks-performance-fix-catalyst-control-center-driver-coming-boost-tessellation-performance/

Now, I say these things not because I am an AMD fanboy. I have a Nvidia GTX 770 in my system, which I built 13 months ago.

No, the reason I say these things is that first off, AMD video cards can and do run Hairworks well. You just have to change the setting. Second, AMD created TressHair. Years ago. And when they created it, they optimized it so that TressHair worked equally well on both AMD and Nvidia cards. And then, to top things off, they posted the source code for TressHair online, for anyone to see and use. Somewhere about the same timeframe, Nvidia started working on Hairworks. In the version of Hairworks in Witcher 3, not only does Hairworks not run well on most video cards by default, but Nvidia makes the developers of anyone that uses their Hairworks sign an agreement forbidding them from optimising the code for any competitors hardware, and here is the hilarious part Hairworks only runs well on Nvidia Maxwell GPU's. Even Nvidia Titan fails to run Hairworks well, as does last generation GTX 700 series cards, and all older ones. So it appears that Hairworks ONLY optimised for Nvidia Maxwell GPU's. Everyone else is screwed over.

Now, back to TressHair for a second. TressHair, which runs equally well on both AMD and Nvidia hardware, runs faster on Nvidia hardware than Hairworks does. So why is Nvidia insisting on running inferior code that screws over so many customers of both their own cards and all AMD cards. Or at least it tries to.

The difference here between how AMD played the game, and how Nvidia plays it is disturbing. It is playing dirty. This is an industry where we need our graphic cards to be able to run everything well. If we cannot get that, then we are going to have to buy two video cards, and start swapping out the video card to match who the game is optimized for, which would be insanity.

So somehow, we have to get the message to Nvidia that they need to play the game fairly.

Found a benchmark with a GTX980, 1080p/ultra giving 66 fps average, 49 fps minimum so that's better. Still without Hairworks though.

Last one - 76 fps av, 63 fps min, 1080p/ultra no hairworks, GTX980. Add in Hairworks gives 56 average, 28 min.

I'd say that a GTX980 or 980Ti may give you 50 fps and up, should certainly give you 40 fps and up, but you're going to have to live without Hairworks.

Monday is the AMD announcements... Watch prices tumble within 2 weeks...

Then getting a second GTX 970 for SLI will become more affordable.