Windows – How to interpret Windows Task Manager


I run Windows 7 RC1, which uses the same WTM from Vista. When i look at the processes, there some columns I'm not sure what the differences are:

  • Memory – working set
  • Memory – private working set
  • Memory – commit size

can anyone tell me what they are?

Best Solution

From the following article, under the section Types of Memory Usage:

There are two main types of memory usage: working set and private working set. The private working set is the amount of memory used by a process that cannot be shared among other processes, while working set includes the memory shared by other processes.

That may sound confusing, so let’s try to simplify it a bit. Lets pretend that there are two kids who are coloring, and both of the kids have 5 of their own crayons. They decide to share some of their crayons so that they have more colors to choose from. When each child is asked how many crayons they used, both of them said they used 7 crayons, because they each shared 2 of their crayons.

The point of that metaphor is that one might assume that there were a total of 14 crayons if they didn’t know that the two kids were sharing, but in reality there were only 10 crayons available. Here is the rundown:

  • Working Set: This includes all of the shared crayons, so the total would be 14.
  • Private Working Set: This includes only the crayons that each child owns, and doesn’t reflect how many were actually used in each picture. The total is therefore 10.

This is a really good comparison to how memory is measured. Many applications reuse code that you already have on your system, because in the end it helps reduce the overall memory consumption. If you are viewing the working set memory usage you might get confused because all of your running processes might actually add up to more than the amount of RAM you have installed, which is the same problem we had with the crayon metaphor above. Naturally the working set will always be larger than the private working set.