You may not see any difference between an i5 and an i7.
Depends how many THREADS (simultaneous CPU processes) your audio editing and graphical editing software needs.
For 1-4 threads, i5 and i7 perform the same. For 8 threads, an i7 is 30% faster than an i5
Faster clock speed also makes your CPU complete tasks faster, but the difference between 3.5GHz and 4GHz is not really obvious when using a PC .