Assuming the same clock speed, the Core i5 has roughly 25% more computational power than a Llano A6-3600. Therefore, a Core i5 @ 3.3GHz would be about as equivalent to an A6-3600 clocked at 4.1GHz.
Much much more faster.....all round....both in single as well as multi-threaded stuff
In short, the i5-2500 will destroy the A6 without any mercy, there's no competition here, only a heavy, one-sided victory for the i5
I don't think they're relevant comparisons, they're both completely different CPUs aimed at different markets and uses. What specifically do you need either one for?
At the most strict view, the i5 has absolutely night/day performance in terms of CPU power, but the A6 has better onboard graphics.