You can give a check here: http/www.notebookcheck.net/Mobile-Processors-Benchmarklist.2436.0.html
To kinda sum those numbers up, i3 and i5 processors are faster clock for clock when compared to Core2Duo CPUs. An i3-330M at 2.13ghz is roughly equal to a Core2 P8600 @ 2.4ghz. An i5-430M @ 2.26ghz is roughly equal to a T9500 @ 2.60ghz.