your hardware is fine without overclocking, my amd apu at 2.6 handles it just fine. your i7 has enough bandwidth to work just fine. and your 550ti is fine as well, again, i run dolphin on an amd apu at about 80%.
your best bet is to just make a change and test. try disabling lock threads to core. if that doesn't give you a better result, disable dsp lle on core. test, rinse and repeat. but start with those 2.
also, what resolution are you running. reduce the IR to 1x until you find the optimal, turn off AF. and change to DSAudio (or whatever the other option is).
either way, results will vary for everyone, so you really just have to keep making a change, test, make another change, test, etc
your best bet is to just make a change and test. try disabling lock threads to core. if that doesn't give you a better result, disable dsp lle on core. test, rinse and repeat. but start with those 2.
also, what resolution are you running. reduce the IR to 1x until you find the optimal, turn off AF. and change to DSAudio (or whatever the other option is).
either way, results will vary for everyone, so you really just have to keep making a change, test, make another change, test, etc