AC4 and planetside 2 are two heavily cpu reliant games, if you can't maintain 60 fps it's your cpu not your gpu.
In the case of planetside 2 if I remember right it also has an ingame supersampling resolution slider that will murder your framerate because you won't be playing at 1080p but at a much higher resolution downsampled to 1080p. But really planetside 2 requires a powerful cpu even after the performance patch.
As for watchdogs, shitport is gona shitport... it's pointless to buy more powerful hardware for disaster ports
5 years ago saint's row 2 was a shitport that would run poorly on the biggest monster pcs, even 3 years after release it would not hit 60 fps on a monster pc of that time. That doesn't mean people should buy a faster pc based on that game... it was pointless
Idk if you can even hit 60 fps steady on it on today's high end pcs... and it looks like a fucking ps2 game
You just have to accept that no matter what hardware you have , a bad broken game is a bad broken game, there is no escaping it. The only escape is not buy the shitty game of the shitty dev who never deserved your money to begin with.
When your toast gets burnt you throw it away.