How to Know Which Process Is Using the Most CPU
Sort Task Manager the right way to find the exact program slowing your computer down.
Your computer is running slow and you want to know exactly which program is responsible. The answer is in Task Manager, sorted the right way — in under a minute you have the answer.
Sort by CPU usage
- Press
Ctrl + Shift + Esc. - In the "Processes" tab, click the word "CPU" in the column header.
- One click sorts from highest to lowest usage — the process using the most processor time appears right at the top.
If you need the full context on how to interpret the rest of the columns and what to do with a process that's misbehaving, our guide on how to use Task Manager covers it in detail.
A very common confusion: "System Idle Process"
If you see something called "System Idle Process" with a very high percentage, don't worry — it's the exact opposite of a problem. That "process" represents the time your CPU isn't doing anything — the higher its number, the freer your processor actually is. It's one of the most common points of confusion when looking at this list for the first time.
Another common false alarm
Task Manager itself uses some CPU while it's opening and drawing on screen — if you see a high spike right when you open it that drops straight away, that's normal, it's just the tool itself starting up, not a real problem.
For more detail: Resource Monitor
If Task Manager falls short, type resmon in the
Windows search box to open Resource Monitor — the "CPU" tab shows you
a more detailed breakdown, including the "associated handles" for
each process, useful for harder-to-diagnose cases.
Tip: if the same process keeps reappearing using a lot of resources right after you close it, and you don't recognise its name at all, search for that exact name online before anything else — some malicious processes use names very similar to legitimate Windows ones to go unnoticed.
Frequently asked questions
Is it safe to close any process using a lot of CPU?
Not just any. If the process's 'Type' isn't 'App' (it's a Windows process), forcing it to close can cause instability. Our guide on which processes you can close safely covers this more carefully.
Why does 'System Idle Process' show such a high number?
Because it represents the opposite of what it looks like: the percentage of CPU that is NOT being used. A high number there is a good sign, not a problem.
Does Task Manager show usage in real time?
Yes, it updates constantly while the window is open — that's why it's normal to see the order of processes change depending on what each one is doing at any given moment.