Pagefile and RAM Performance and Stablity question!

Contrary to popular belief, virtual memory and the page file are not the same thing.

Virtual memory is an addressing mode which organizes physical memory into pages (normally 4KiB each, but in certain modes 2MiB pages can also exist) and provides each running task with its own virtual memory space. This address space starts at address 0 and spans all the way up to the top of the memory space allowed by the architecture. For an x86 machine running in 32-bit protected mode this spans from 0x0 to 0xFFFFFFFF, and for an x86 machine running in 64-bit long mode this spans from 0x0 to 0xFFFFFFFFFFFFFFFF. Naturally the address space cannot be full for each application, so most of the addresses are simply uninitialized and attempting to access them will result in an exception.

Virtual addresses are translated by the CPU into physical addresses through a process known as a page walk. The details aren't too complicated, but I'll skip over it for purposes of brevity as it's somewhat tangential to the point (if you want to know more, just ask). This translation process allows all running tasks to have their own code and data start at address 0 without worrying about collisions as they will all be mapped into different physical addresses. In essence, it allows each task to run in isolation without any knowledge of other running tasks and without the ability to read or write to memory other than its own or that which it shares with the OS.

This mode can easily be extended to swap application memory from the DRAM to a page file on a hard disk in a fashion that is transparent to the application. The swap is visible on the physical side, but invisible on the virtual side. Over time committed memory (assigned to a task) that is infrequently accessed will be moved to the hard disk such that the DRAM can be used for other running tasks. When an application accesses a memory address that's been swapped to disk, the CPU generates a page fault and the OS handles the fault by moving the desired page from the page file back into memory.

If you have gobs of DRAM in your system you can certainly disable the page file entirely. However, it is recommended to leave at least 1GiB available on a hard disk to store kernel crash dumps as these cannot persist in DRAM through a reboot.

Having a larger pagefile is fine. If I were you I'd leave about 16GiB on your HDD, and disable it on your SSD. Since you're using Windows 8.1 it may disable it on your SSD by default if your HDD was present upon installation.

eh?