# MAX memory on a 64 bit OS



## f28ang (May 4, 2009)

Hi
I am looking forward to using a 64 bit OS like Windows XP 64 bit
i was wondering wat is the max memory that i can use 
i am a avid gamer so i believe that more the memory better n smoother my system work 
thats the whole reason for me to go for a 64 bit OS as the normal os supports only 4 Gb

Eagerly waiting for reply
Any Info ll be helpful
Regards


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## Jelly Bean (Aug 13, 2009)

Hello and welcome.

A 32 bit OS reconises 3.25 gig RAM a 64 bit OS reconises 4 gig and over.

You must remember adding more RAM your mainboard must support more RAM.

If your mainboard supports the added amount of RAM you could add 4 gig upto 8 gig I suppose.


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## Tyree (May 10, 2009)

64 Bit XP drivers are very limited and often not stable.
If you want to go 64 Bit, go with Vista or, better choice, wait for Windows 7 in Oct.
4GB of RAM is more than sufficient.


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## Mikhalkov (Jan 23, 2009)

Here's the theory behind it:
For 32-bit, the most RAM that can be addressed is 2^32 (in bytes)
2 ^ 32 = 4,294,967,296 Bytes
Divide by 1024,
4,294,967,296 Bytes / 1024 = 4,194,304 KB
4,194,304 KB / 1024 = 4,096 MB
4,096 MB / 1024 = 4GB

For 64-bit, the most RAM that can be addressed is 2^64 Bytes
2 ^ 64 = 1.844 * 10^19 Bytes
1.844 * 10^19 Bytes / 1024 = 1.801 * 10^16 KB
1.796 * 10^16 KB / 1024 = 1.759 * 10^13 MB
1.748 * 10^13 MB / 1024 = 1.717 * 10^10 GB
1.702 * 10^10 GB / 1024 = 16,777,216 TB
16,777,216 TB / 1024 = 16,384 PB (Petabytes)
16,384 PB / 1024 = 16 EB (Exabytes)

Obviously, there's no motherboard that can handle that much RAM, but perhaps sometime in the distant future, everyone will have 16EB of RAM.


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