Maximum size of application memory space on 32 (x86)? 2 Gb or 1 Gb?

Question

What amount of memory is available (theoretically) to application on 32 bit system? Different OSes? 2 or 1 Gb?

thx!

Answer 1

It depends on the OS.

32-bit Windows by default allocates 2GB to the application and 2GB to the kernel, so theoretically your application could allocate up to 2GB. You can change this allocation on some versions of windows by using the 4GT boot flags. Check out this MSDN article for more information.

64-bit Windows has much more, something like 8TB.

I think Linux in general has 3GB of user space, but I'm not completely sure.

Answer 2

All of the memory is available to the application. There may be limits on how much address space the application can use, and thus how much memory it can map at one time. But typically, the application can use every single byte of physical memory if it wishes to.