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I guess you stopped reading there. 4 is not enough. I have a work iMac that can only take 4 gigs of ram. safari/firefox/chrome easily get to 1.5 gigs and above in no time flat. Open up word, and I am already getting pegged.

go with 8

The more ram you have the more the operating system will use. The system frees ram as you need it. firefox and word don't take up 4gb unless you have an insane amount of tabs open.
 
The more ram you have the more the operating system will use. The system frees ram as you need it. firefox and word don't take up 4gb unless you have an insane amount of tabs open.
define insane.

They don't have to take up 4 Gigs by themselves. But if they take up 1.5 + OS + whatever else you have open = lots of swapping with 4Gigs of RAM.
 
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