you have to get the same speed in the new ram as what the original ram is
Count how many ram slots you have and take the original ram to the store and buy more the same speed. Some ram that suppose to work at backward compatable speed do not, if the computers power supply is a bit weak.
RAM and Virtual Memory check – Any OS that has XP type taskmanager
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Open up the internet to eg yahoo answers and have a few things open .(eg Word excel or a couple browser pages)
If you normally play music, play that. Close down anything else just for this test.
Open Task manager >performance tab
Look at the RAM usage in the physical memory (k). If you are using more than 60% of your RAM while your computer is only doing the above then there is not much left for video or games. You may need to install more RAM
1 Gig for XP, 2 Gig for Vista
Look at the PF usage. That is the virtual memory (Paging File). Your virtual memory minimum setting should be more than what is being used at this moment.
Your virtual memory maximum should be set to 1.5 times the amount of RAM you have. Eg 1 gig RAM, therefore 1.5 gig Virtual Memory
Right click my computer icon >properties > advance tab >performance settings > advance tab > virtual memory change > select the drive with the operating system on it (normally C:) bullet custom. Enter the max value as one and a half times the RAM you have.
Remember to have your minimum setting entry,more than what was being used in the test.
In this example, if Ram is 1 gig and the PF was using 360 Meg, then I choose 500 min and 1500 max. >set
Your computer is now set for optimum performance for the RAM you have.