Why memory usage of a Process is different in different systems

[rrapheall]

When I run for example say "notepad" in different PCs, each PCs task
manager show different values of "mem usage" "VM size", "Paged pool" and "NP pool".

I checked this in similar configuration machines, but even then in
both system I got different memory usage??. Why is this soo?.

It would be very much appreciated if anybody can also provide me with
some links where I can get more information abt why these difference
in the memory usage.

[Lars(NL)]

System page size.

I quote from the 'dwSize' parameter description of VirtualAlloc on MSDN:
dwSize
[in] The size of the region, in bytes. If the lpAddress parameter is NULL, this value is rounded up to the next page boundary. Otherwise, the allocated pages include all pages containing one or more bytes in the range from lpAddress to (lpAddress+dwSize). This means that a 2-byte range straddling a page boundary causes both pages to be included in the allocated region.

[PeejAvery]

I checked this in similar configuration machines, but even then in
both system I got different memory usage??. Why is this soo?.
Because no two computers are the same. Don't forget that other software/processes currently running can affect it as well.