DX12 will bring performance to amd,nvidia and intel , i would be reluctant to say up to 80% coz that its kinda too optimistic it depends much on how developers chose to use DX12 and optimize their games. for witcher 3 DX12 patch is gona be released but till then we can just speculate. true dx12 games when they get made will show us the real deal till then its mostly tech talk.
Before i buy i just wanna know if i can run it smoothly at 1080p not expecting 60 fps here.. The Problem is my CPU
GTX 980 OC edition
Intel i5 760 @ 2.80 GHz
32gb Gskill ripjaws memory
I can run all recent games on Ultra Setting (GTA V, DA:I, Far Cry 4 etc)
ur cpu is kinda rly old but if it had no problems with those other games it should be smooth on witcher too if cdpr optimized it rly nicely,but if an 8(or 4+4HT style)core cpu is needed for max than u might have some framedrop there