The thing is after I restart the comp it's still run really slow and laggy, evenwhen I type this or switching browser tabs, scrolling it has about .30 sec delays. Everything become very laggy.
I quickly realised after buying my 2010 i5 that 4Gb RAM was not enough to run well. Bumping up to 12Gb by adding another 2 x 4Gb sticks was the answer, all is nice and smooth now.
Otherwise, with FF taking up over a quarter of your memory, try changing your browser or disabling any extensions the might be sapping the RAM.