Windows Inside & Out · Task Manager & Performance · Lesson 1 of 5

Reading the Performance Graphs

Learn what the CPU, memory, disk and network graphs in Task Manager tell you.

Four graphs, four jobs

Task Manager is a Windows tool that shows what your computer is doing right now. Open it with Ctrl+Shift+Esc, or right-click the Start button and choose Task Manager.

On the left side, click Performance. You will see small live graphs. Each one tracks a different part of the computer. Click a graph to make it big.

• CPU: the processor, the chip that does the thinking. The graph shows how busy it is, from 0 to 100%.
• Memory: the short-term workspace, also called RAM. Open apps and files sit here while you use them.
• Disk: the storage drive that keeps your files and apps. Its graph shows active time, the share of time the drive is busy reading or saving.
• Wi-Fi or Ethernet: your network connection. It shows how much data is being sent and received.

Many computers also show a GPU graph. The GPU is the graphics chip that draws pictures and games on the screen.

Spikes are normal. A graph jumps when you open an app, load a web page or start a download. Then it settles back down. What matters is a graph that stays high for a long time while you are doing very little.

Looking at these graphs is completely safe. You are only reading, not changing anything.

On a Mac, the matching tool is Activity Monitor. It has tabs for CPU, Memory, Energy, Disk and Network.

On the practice computer, open Task Manager and click Performance. Then open each graph: CPU, Memory, Disk and Wi-Fi.

In use, Available and a busy disk

Click the Memory graph. Below it you will see a few numbers. Two of them matter most.

• In use: memory that apps and Windows are using right now.
• Available: memory that is ready to give to the next thing you open.

Windows likes to keep memory busy. It keeps recently used things in spare memory so they open faster. That is normal, and Windows hands that space back when an app needs it. So a high In use number alone is not a problem.

The warning sign is when Available gets very low and the computer feels slow. Then Windows has to move things out to the disk, which is much slower than memory. Closing apps and browser tabs you aren't using frees memory. If it happens every day, the computer may need more RAM.

Now look at the Disk graph. Sometimes it sits at 100%. That means the drive is busy all the time, so everything else waits in line. Apps open slowly and clicks feel late.

The usual causes are often temporary:

• Windows Update downloading or installing.
• A virus scan running.
• Indexing, when Windows builds a list of your files so search is fast.
• Cloud storage, like OneDrive, syncing lots of files.

Older computers with a hard drive, a disk that spins inside, hit 100% much more often. Newer ones use an SSD, a fast drive with no moving parts.

If your disk sits at 100% for hours, every day, the next lessons show how to find the cause. But often the best first step is simple. Give it a few minutes and let the work finish.