What is pf usage in the task manager?

In window Task manager , what's PF Usage ? And system Cache Memory ? And is it possible to empty it?

• Answer:

  PF = Page File. It's disk space where virtual memory pages exist when they are not in physical memory (i.e. memory chips). That number shows you how much virtual memory is existing on disk... the lower the better. System Cache is memory used to store often referenced disk pages. So these two mechanisms are sort of the opposite of one another... the Page File is a place to store seldom used memory on the disk, and the System Cache is a place to store often used disk blocks in memory. There is probably some way of clearing or flushing the System Cache, but it will only result in slowing down your computer. In principle, there's no way to flush the page file because the whole reason for its existence is that you don't have enough physical memory to store the pages you are using.