Ugh, this, Divinity: OS and the new Torment makes me want to build a PC. Then I look at the Witcher 3's requirements and I cry.
edit: WTF, why 4GB of RAM? I have 2GB on this PC only...
Most of these great RPG's don't require a beast of a PC to play.
Build a small form factor PC with a 750 ti and a last gen i5 and you'll be fine, and it should fit in a $600 budget.
You won't be maxing Witcher 3 at 60 FPs, but the 750ti has been outperforming the PS4 in most games, so you're looking at better than PS4 performance with that and most other games. 1080p medium-ish settings at a solid 30 FPS.
And unlike a PS4, which is stagnant hardware for the next 7+ years, in a few years, a modest investment means double, triple the performance of a current gen console. You can go back and replay WItcher 3 at max 60 + FPS (free ultra HD remastering, instead of the PS4 asking you for $60) or just enjoy new games at way better than console settings.