How to Use Windows Task Manager to Diagnose Performance Issues

Windows Task Manager is one of the most useful built-in tools for understanding why your computer is slow. Here is how to read it and what to do about what you find.

Category: Performance Tips | Read time: 3 min | By Midland Computers

Task Manager: Your Computer's Dashboard

Most people only open Task Manager to force-close a frozen program. But it is actually a powerful diagnostic tool that can reveal exactly why your computer is slow, overheating, or misbehaving.

**How to open Task Manager:** Press **Ctrl + Shift + Esc**, or right-click the taskbar and select **Task Manager**. Click **More details** if you see only a simple list of open apps.

The Processes Tab

This is the most useful tab for diagnosing slowness. It shows every running process sorted by resource usage.

  • **CPU column:** Click to sort by CPU usage. If a single process is using 50-100% CPU constantly, that is abnormal. Common culprits include antivirus scans, Windows Update, and malware.
  • **Memory column:** Shows how much RAM each process is using. If total memory usage is consistently above 80-85%, you may need more RAM.
  • **Disk column:** High disk usage (90-100%) by a single process often indicates a struggling hard drive, Windows Update running in the background, or a malware infection.

    • The Performance Tab

    This tab gives you live graphs of your CPU, RAM, disk, and network usage.

  • **CPU:** Should be under 20% during idle. Sustained high CPU at rest suggests a background process (update, antivirus, or malware).
  • **Memory:** Watch the "Available" figure. Under 1-2GB available during normal use means more RAM would help.
  • **Disk:** The drive should be near 0% when you are not actively doing anything. Persistent high disk usage at idle often points to an ageing hard drive that may be failing.

    • The Startup Tab

    This tab shows all programs that launch automatically when Windows starts. Programs with **High** startup impact slow down your boot time significantly.

    Right-click any unnecessary startup programs and select **Disable** to speed up your boot time. Be cautious — only disable things you recognise and do not need at startup.

    When Task Manager Points to a Bigger Problem

    If Task Manager reveals:

  • Persistent 100% disk usage (possible drive failure)
  • Unknown processes using significant CPU (possible malware)
  • RAM constantly maxed out despite closing programs

    • ...it is worth getting a professional diagnosis.

    Midland Computers provides thorough [computer performance diagnostics and repair in Midland](/services/computer-repairs-midland). Our technicians can quickly identify whether your performance issues need a software fix, a hardware upgrade, or a drive replacement.

    We have helped hundreds of Perth residents get their computers running fast again — honestly and affordably. [Book a diagnostic](/book-repair) or [contact us today](/contact).