I currently have a very low end cpu that is the AMD Athlon ii x2 240 and i was wondering what performance gains i will see from upgrading to a slightly better x4 620. I was also wondering how difficult overclocking would be, because I bought this cpu with a zalman cnps5x, so i would love to give it a try because of the 620's lower clock speed. I have never overclocked a cpu with a locked multiplier, so this would be a new thing for me. Thanks!