A slow Windows 11 PC is one of the most common frustrations in any office. The good news is that most performance problems have straightforward causes — and most can be fixed in under 10 minutes without spending anything. This guide covers the most effective fixes, starting with the ones that make the biggest difference.
1. Disable Startup Programs
The single biggest cause of a slow Windows 11 machine is too many programs loading at startup. Every piece of software that launches when you log in uses memory and CPU before you’ve even opened a browser.
- Right-click the taskbar and open Task Manager
- Click the Startup apps tab
- Sort by Startup impact
- Right-click anything you don’t need immediately and select Disable
Common culprits: Teams (loads faster when you open it), Spotify, OneDrive (if you don’t use it daily), Skype, and any manufacturer utilities that came pre-installed.
2. Check What’s Using Your Resources Right Now
If your PC is slow at this moment, open Task Manager (Ctrl + Shift + Esc) and click the CPU and Memory columns to sort by usage. Anything sitting at consistently high CPU or memory is worth investigating. Common offenders include Windows Update running in the background, antivirus scans, and browser tabs with heavy content.
3. Turn On High Performance Power Mode
Windows 11 defaults to Balanced power mode, which throttles your CPU to save energy. On a desktop, or a laptop that’s always plugged in, switch to High Performance:
- Open Settings → System → Power & sleep
- Click Additional power settings
- Select High performance
This alone can make a noticeable difference, particularly on older machines.
4. Free Up Storage Space
Windows 11 slows down significantly when your main drive is more than 80–85% full. The operating system needs space for temporary files, virtual memory, and updates. Run Storage Sense to clean up automatically:
- Open Settings → System → Storage
- Turn on Storage Sense
- Click Run Storage Sense now
Also check your Downloads folder — it’s common to have gigabytes of old installers and documents taking up space.
5. Upgrade to an SSD (If You’re Still on HDD)
If your PC takes more than 30 seconds to boot, or opening programs feels sluggish even after the above fixes, you may still be running a traditional spinning hard drive. Moving to an SSD is the single most impactful hardware upgrade you can make — boot times drop from 60+ seconds to under 10, and everything opens faster. A 500GB SSD costs around £40–60 and the installation is straightforward on most desktops and many laptops.
6. Adjust Visual Effects
Windows 11 uses animations and transparency effects that look good but cost performance on older hardware. To turn them off:
- Search for Adjust the appearance and performance of Windows in the Start menu
- Select Adjust for best performance, or manually uncheck the animations you don’t need
7. Make Sure Windows Update Has Finished
A major cause of random slowdowns is Windows Update running in the background — downloading, installing, and preparing restarts. Go to Settings → Windows Update and check the status. If an update is pending or actively installing, let it finish (and restart when prompted) before diagnosing further.
8. Run a Quick Malware Scan
Malware and unwanted programs can quietly consume CPU and memory in the background. Windows Defender (built into Windows 11) is capable — open Windows Security → Virus & threat protection and run a Quick scan. If Defender has been disabled or you haven’t run a scan recently, do it now.
9. Check Your RAM
For most office tasks — email, browser, Office apps — 8GB of RAM is the minimum. If you’re regularly running Teams, multiple browser tabs, and Excel simultaneously, 8GB will start to struggle. You can check your current RAM in Task Manager under the Performance tab. If memory usage is consistently above 80%, more RAM is the fix — 16GB is the practical sweet spot for office work in 2026.
10. Restart More Often
It sounds obvious, but many office PCs are left in sleep mode for days or weeks. Windows accumulates temporary files, memory leaks, and background processes that build up over time. A full shutdown and restart clears them. If your PC has been running for more than a few days, try a restart before anything else.
When to Consider a Full Reinstall
If you’ve tried all of the above and the machine is still slow, a clean Windows 11 install may be the most efficient solution. This is particularly true for PCs that have been upgraded from Windows 10 multiple times, or have had a lot of software installed and removed over the years. A clean install takes about an hour and often produces a dramatically faster machine.
