The Witcher 3 is a GPU heavy Game. However, the GTX 770 can handle it pretty well.
System used : Motherboard : MSI Z97 Gaming 5 CPU : Intel I7-4790k GPU : MSI GTX 770 Twin Frozr 2Go RAM : 16go DDR3 @ 1600mhz SSD : Sandinsk SSD Plus 480Go (Unless specified, I don't overclock the CPU, GPU or RAM to record and benchmark)
