In the end, there are vast differences from cpu to cpu even within the same company and same model brand.
The question should be "which can run an audio app to full potential?" The answer would be anything current, lol.
Even with the i5/965 comparison, sure the i5 can run some 30-50 more instances of processing effects, but why care when on runs 120 fx and the other runs 170? When will either ever be pushed to those limits(not accurate calculated numbers, just making a point)?
But still... what specifically about the i5 makes it outperform an AMD 965 despite the AMD technically having better specs? Anybody know? lol i'd really like to know.