A slow computer is frustrating, but it's rarely a sign of serious hardware failure. In most cases, one of a handful of common culprits is to blame — and most of them can be fixed without contacting IT. Work through these checks in order before logging a ticket.
1. Too many browser tabs or extensions
Your web browser — particularly Google Chrome and Microsoft Edge — is one of the most memory-hungry applications on your computer. Each open tab consumes RAM, and some browser extensions run continuously in the background even when you're not using them.
What to do:
- → Close any browser tabs you're not actively using. Aim to keep fewer than 10 open at a time.
- → Restart your browser completely — close it fully (don't just minimise) and reopen it.
- → Review your browser extensions. In Chrome or Edge, go to the Extensions menu and disable any you don't recognise or regularly use.
2. Too many programs starting up automatically
Over time, software installations add themselves to your startup list. These programs all launch when you turn on your computer, competing for resources before you've even opened anything. A cluttered startup list is one of the most common reasons a computer feels slow from the moment you log in.
How to check startup programs
Windows 10 / 11
- 1. Press Ctrl + Shift + Esc to open Task Manager
- 2. Click the Startup tab
- 3. Right-click anything with “High” startup impact and choose Disable
Mac
- 1. Open System Settings (or System Preferences on older macOS)
- 2. Go to General > Login Items
- 3. Remove anything you don't need at startup using the minus button
Only disable items you recognise. If you're unsure about something, leave it and ask IT.
3. Windows or macOS updates waiting to install
When a system update is downloaded and waiting in the background, your computer sometimes slows noticeably — particularly on older hardware. The fix is simply to let the update install and restart properly.
Windows
Go to Start > Settings > Windows Update and check whether an update is waiting. If one is, click Restart now or schedule the restart for a time that suits you.
Mac
Go to System Settings > General > Software Update. If an update is available, install it and allow the restart. macOS updates often include performance and stability improvements.
4. Your hard drive is nearly full
Both Windows and macOS use free disk space as temporary working memory. When your drive is nearly full, the operating system has less room to work with and slows down as a result. SSDs (solid-state drives, which most modern computers use) also become noticeably slower as they fill up.
Rule of thumb
Try to keep at least 15–20% of your drive free. On a 256 GB drive, that means keeping roughly 40–50 GB free at all times. If you're below that, it's time to move files to OneDrive or an external drive.
How to check free space:
- → Windows: Open File Explorer, right-click your C: drive, and select Properties. The pie chart shows used and free space.
- → Mac: Go to Apple menu > About This Mac > Storage to see a breakdown of what's using your disk.
5. An application is using too much CPU or memory
Sometimes a single runaway process — a frozen application, a browser tab with an auto-refreshing video, or a misbehaving background service — can consume most of your computer's resources and bring everything else to a crawl. Task Manager (Windows) and Activity Monitor (Mac) let you see exactly what's going on.
How to find the culprit
Windows
- 1. Press Ctrl + Shift + Esc
- 2. Click the CPU or Memory column header to sort by usage
- 3. If anything unfamiliar is near the top and using >50%, right-click it and choose End Task
Mac
- 1. Open Spotlight (Cmd + Space) and search for Activity Monitor
- 2. Click the CPU tab and sort by % CPU
- 3. Select any process using excessive CPU and click the stop button (✕) to quit it
6. When in doubt, restart properly
If you've worked through the above and the computer is still slow, a full restart often resolves performance issues that can't be traced to a specific cause. Make sure you're doing a proper restart — not just locking the screen or closing the lid.
Do this
Start menu > Restart (not Shut down). Wait for it to fully power off and back on. Let it settle for a minute before opening applications.
Not this
Closing the lid, locking the screen, or using “Sleep” — these don't clear temporary files or refresh system memory.
When to stop and call IT
If you've worked through all of the above and the computer is still slow, or if you notice any of the following, it's time to get IT involved — the cause may be hardware-related.
- !The computer has been slow for weeks and nothing has changed it
- !You hear clicking, grinding, or unusual fan noise
- !Applications crash regularly or the screen freezes and requires a hard restart
- !The computer is more than 5–6 years old and increasingly slow despite the above steps
- !You see error messages about disk errors or memory failures
Need help right now?
If you're a StormDotCom client and the slowdown is affecting your work, get in touch. We'll remotely diagnose what's going on and get things running smoothly again.
Contact the Help Desk