How much XP 32 bit "sees" depends on the chipset and on the BIOS capabilities and settings.
One of my mainboards had the option to remap I/O addresses to above the 4 GB boundary, and XP 32 bit "saw" a full 4 GB of RAM.
In other systems it may be 3 GB, or 3.25 GB, or 3.5 GB.

This number is the total amount of RAM that the OS can assign to applications.
The other limit is how much memory a single application/process can get. In normal circumstances, that's 2 GB per process. When started with the /3GB switch, it's 3 GB per process - if the process is able to use it. Poser 7 is compiled with the LARGE_ADDRESS_AWARE switch, so it will be able to use that extra GB. Poser 6 and older, and DAZ|Studio, are "pure" 32 bits applications that will only use 2 GB of address space, even if there is far more available.

Standard 32 bit applications will still be limited to 2 GB on a 64 bit OS.
LARGE_ADDRESS_AWARE applications will be limited to 4 GB on a 64 bit OS
64 bit applications will be limited to 128 GB on XP Pro 64 bit. I don't know about Vista 64 bit, Windows 7 64 bit or Linux, but it won't be less than 128 GB.

The pen is mightier than the sword. But if you literally want to have some impact, use a typewriter

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