Max address space and pagefile

[manveruppd]

OK, this is probably the 6th pagefile discussion thread I've posted in, but...

If I'm using 4GB of RAM on a 32-bit OS, can Windows actually use the pagefile? How does that work? Surely 4GB is the maximum TOTAL memory the OS can address, whether it's real or virtual, so what's the point of even setting a pagefile?

Please get as technical as you can in your answers, I find this sort of stuff interesting.

 

[swinnie]

I thought 32-Bit couldn't address 4Gb of RAM, I thought the only way to use 4Gb of RAM is to have a 64-Bit version. As a 32-Bit OS can only see and use approx 3 - 3.5Gb?

Might be wrong...

 

[Ethics]

It's all to do with virtual address spacing you can have upto 4GB of address space on a 32bit OS this address space is used for memory of all devices (PCI, GFX etc.) so when that is reserved, you get 3.5 or so left.

pagefiles do not use the virtual address spacing, infact they take it and put it in small chunks on the HDD, freeing up so of it.

You may find this article useful

http://support.microsoft.com/kb/555223