With Watchdogs I had significant issues running it on a i7 4770, MSI GTX 770 2GB OC (with higher overclock done by me), 16GB of 1866 DDR3. It's not a low end system by any means. Of course this was pre-patch, but it is a highly damanding game. I have seen the game running on a system with an AMD 8350 8 Core CPU (this game only uses 4), a 4GB GTX 760, with 8GB of RAM at about 38-52 FPS. I would try the GTX 760 4GB, if thats not enough you may want an i5. The game itself really need quite a bit of VRAM, and was a bad console port. So if you want a decent gameplay experience you will need to upgrade or just play on console which would be cheaper short term. But a PC upgrade would do you better in the long run. Bear in mind all the above...