As im reading all the post's here; im seeing a great number of people upgrading their RAM to say 4gig, or 6 gig (can even go higher)
Now; if you are running a 32bit operating system, Win7 WinXp Vista(whats the point of living if you have this

64Bit Operating systems, change this, and have the ability to access over 246GIG or RAM, (From SD to DDR3 2000Mhz)
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So please guys and girls; if your not willing to go to a 64Bit Operating System, dont even bother adding more then 3gig of RAM
More info can be found here
RAM Access