heftig wrote:For every 32-bit process itself, yes. But the system will be able to use the whole 4gb.
Not entirely true. Under 32-bit XP, processes are given 2GB of the address space, the other half is given to the kernel. This prevents thrashing in kernel mode, which is never a good idea. You can use the /3GB switch in boot.ini to change the ratio to 3:1 (same as Linux), and couple it with /PAE to enable Physical Address Extensions (hardware support for 36-bit addressing) to loosen Windows' belt a bit.
heftig wrote:For every 32-bit process itself, yes. But the system will be able to use the whole 4gb.
Not entirely true. Under 32-bit XP, processes are given 2GB of the address space, the other half is given to the kernel. This prevents thrashing in kernel mode, which is never a good idea. You can use the /3GB switch in boot.ini to change the ratio to 3:1 (same as Linux), and couple it with /PAE to enable Physical Address Extensions (hardware support for 36-bit addressing) to loosen Windows' belt a bit.
Correct, but none of that is really a good idea and can often lead to windows crashing. According to anandtech, you can actually set the ratio anywhere you want, but windows gets pretty BSOD happy at anything under 1.3 GB for the kernel.
The ratio is only configurable for Vista. Everything older can only be set to a 2:2 or 3:1 ratio. PAE is the least likely to cause problems, because pointers are still 32-bit.
