AMD / Intel and graphics processing

If you play on-line graphic intensive video games where you must battle with other users, get i7. Otherwise, i5 is enough for photo editing. In fact the computer will be waiting for you 99% of the time.

A system with good video card is always faster than without. i5 + video card is definitely faster than i7 alone.

If a software is written to take advantage of hyperthreading than turning it on or off will make a difference. Also, certain operation does not need hyperthreading.

I hope this helps.