How to check if your system needs more RAM
1.Press the Ctrl + Shift +Esc key for win7 if xp press Ctrl+ Alt+ Del
2.Now click on Task Manager and select the Performance tab.
3.Look just under midway down on the right and you will see a box labeled Physical Memory (K). Read the total. For example I have (1046528 KB, which is nearly equal to 1 gb)
4.Look at Commit Charge (K) The total there will be how much memory is being used. You will also see a Peak under that total which tells the highest amount of memory used since the last reboot. If the Peak is lower than the Physical Memory total, then you don�t need additional memory. If the total Commit Charge is higher than the Physical Memory Total, then additional memory would give you a significant performance boost .