Battlefield 4 1080p Maxed out settings
Crisis 3 1080p maxed out settings
Far Cry 3 1080p maxed out settings
Tomb Raider 1080p maxed out settings
Watch Dogs 1080p maxed out settings
Yea, ouch. In those games you want a quad core, Tomb Raider being the least exposed to framerate issues with dual core.
You'll want 8GB system RAM and intel i5.
Better yet, i'd say look for i7 if budget allows, otherwise fastest i5 you can afford. The 4590 for $200 is nice.
I run a 280x on a Haswell Pentium, the G3258 dual core no hyperthreading. It does fine for stuff like,.. well it crushes stuff like.
RE5
HL2 + Episodes
Portal 1+2
Max Payne 3 (testing now, may be wrong on this)
Alan Wake
Sleeping Dogs
So the i3 you have is fine for 280x IMO depending on game selection, but your game selection (and new AAA games dropping from here on out) are going to want fast i5 or i7.
After having used the 4690k at 4.4ghz i'd say just get the i7 4790k if you can afford it and want to keep from being CPU bottleneck in the newest games. Not a lot of folks would agree with this though. If you want the 60fps mins, which 280x can deliver depending on graphics settings at 1080p, then you want fastest cpu you can afford.