Physical memory full but can't seem to find what process is causing it

Question

I'm having a problem with my laptop from time to time, sometimes it get's really slow and when I check my task manager it says something like: Physical memory 91%

When this is happening windows starts to swap memory to the hard disk so it all gets really slow. Although when I count all values at Memory usage I don't get anywhere near the 4gb that is in my laptop.

I got the check ticked to show processes from all users and also in the Performance Monitor (from windows 7) it says I have about 100 mb left in my memory, but still, counting all values there doesn't come near the 4gb.

Does anyone have any idea how to really see what process is using the memory?

Answer 1

The memory is not being used by a process, it's being used by the operating system. Modern operating systems only go to the expense of making memory free when they absolutely have to. Since nearly 10% of your memory is free, the system does not need to make memory free and so it doesn't do so.

Unless some process suddenly needed more than 10% if your memory, making more memory free would be completely wasted effort. Why would you want your system to be doing more work when it's already bogged down?

Think about it this way: if more memory were free, then less memory would be holding stuff. Less memory holding stuff would mean more stuff the system needed would be on disk and not in memory. So that would mean that disk I/O would get worse if more memory was free.

For some reason, your system has a high I/O load. It is, smartly, using as much memory as possible to reduce that load.