yes, buy i7 and you will notice 10-15% performance increase
I beg to differ. Unless the OP video encodes/streams/renders etc it isn't that much.http://www.techpowerup.com/reviews/Intel/Core_i5_3570K_and_i7_3770K_Comparison/8.html
While a new 4770k will, it is because haswell vs Ivy. A 4930k would be a nice upgrade too, but the OP would not see as much increase.