It's up to you !
Sadly there are some games where just one core is being used (Starcraft II)... But there are many others as you can see in the video where 12-16 threads are been used.. If you pay attention there is a point where 6700K is loaded all cores 100% and its not able to keep GPU at 99% while 5960X is balancing happily the load in all cores.(video/ min 2:16)
The point is: what is your budget? You'll play and work extremely well with all CPUS. 2011-3 is more future proof. If your plan is keep your computer for a long time go for 2011-3, but if you will change your computer in <2 years go for 6700K.
And, well as you seen in the video, there are more games using more than 4 cores than people thought, although 4 cores are currently enough to play in best conditions.
Future is coming fast. AMD Zen is almost here. Next year cores will make a difference ...
Edited by damarad21 - 8/26/16 at 10:24am