Does changing the process priority in Windows Task Manager cause problems?

Question

When changing the priority of a process, there is a warning about system instability.

I am running a Machine Learning algorithm and the Normal priority makes the computer unresponsive. Does changing the priority of this process cause problems or affect the process (besides making it run slower)?

Solution 1

No, it's just a warning. You probably aren't going to cause any problems by turning the priority of a process up or down a notch. And there won't be any irreversible damage; anything you do mess up can be fixed by a restart. Just make sure to save your work first before experimenting!

There are a couple of common things that can go wrong (and thus that you should watch out for):

1. You can crank up the priority of a non-system process so high that it can cause the system to become unstable and non-responsive because the system processes don't get enough time.

2. You can crank down the priority of a system process so low that it doesn't get enough time, causing your system to become unstable and non-responsive. (Although I think they've fixed some of this more recently by preventing you from altering the priority of certain so-called "critical" system processes.)

In my experience, assuming a decently fast and stable machine, as long as you stay away from the "Real Time" option, you will be fine. Turning non-system process down in priority level is even less likely to cause harm.

Solution 2

If the process you're adjusting interacts with another process, you could potentially create a priority inversion, which is one way to get a deadlock (i.e., it could cause the process or the one it's interacting with to hang).

But if it's just a standalone program that's busy computing, dropping its priority a notch is not likely to cause any problems.

The stability problems mentioned in the warning are an issue only if you change the priority relative to dependent system processes.