For gaming, i7 may not make any such performance increases as compared to the i5. Current gen games are not using more cores/threads hence i5 is more than enough to fulfill any gaming experience. With i7 we have two threads per core making it total 8 threads in 4 cores with hyper threading. Desktop apps, graphics rendering, video editing, CAD etc these are applications which take too much CPU resources hence i7/Xeon is recommended for them. But if you are building only gaming and normal desktop use, stick with i5 and save some bucks and put them into buying powerful GPU.