RAM/per app/CPU thread

[Abaregi]

12

 

[Nothinman]

On a 32-bit system there's 4G of virtual address space available. The kernel splits this between itself and the currently running process and on Windows that's a 2/2 split so the kernel gets 2G of VM and each process gets 2G of VM. On Linux this is a 3/1 split by default and there are patches to even make it a 4/4 split but the cost of fully reloading the TLB at every context switch is pretty high so it's not recommended. It's possible to make Windows use a 3/1 split with the /3GB kernel switch but even after that Windows will still only give each process 2G of VM unless that binary is marked LargeAddressAware.

On current AMD64 systems there's 256TB or 48-bits used for virtual address space available to 64-bit binaries. Future CPUs can have that raised to 64-bits to allow for 16EB of VM. 32-bit binaries are still limited to 2G unless marked LargeAddressAware and then Windows will give them the full 4G. On 64-bit Linux 32-bit processes default to having the full 4G available.