Browsers freezing and slow

I have a macbook pro 15 early 2011 model 2ghz i7 and i have upgraded to 8gb ram...my macbook is always connected wirelessly to the internet and i have tried ALL browsers. Safari 6.0.2, Google Chrome and Firefox and all suffer the same problem.. They all start to freeze and get very slow. I am constantly having to reload pages even when playing games on facebook... I have upgraded to mountain lion and it seems to have become worse... this is my first time with a mac and to be honest this is starting to sway me back to a pc.. it is not just sometimes it is doing it everytime..please help me fix this

it did it with the old ram also...

it can happen with one tab only.... and no i havent but i will give them a try

still happening even just opening this page took forever and seem to freeze half way through loading

I am also noticing that some applications are freezing as well... I am a dj and have the serato software and lately i get the program freezing and the little apple beachball for a good 30 sec to a minute

i did hardware test it is all fine no problems .. I also verified permissions and verified disc and there were no issues... i just dont understand what could be causing it