Start with a restart
The first thing to do is a full restart. A computer left on for a long time often has programs that never quit holding on to memory, or an unfinished update running in the background. Closing the lid or going to sleep is not a restart. Some operating systems use a fast startup feature, so shutting down and turning back on does not fully start fresh; choosing Restart from the menu is the reliable option. If it is fine right after a restart but slows down again over time, a particular program is probably using more and more resources.
See what is using the resources
Operating systems include a tool that shows how much processor, memory, storage and network each program is using. On Windows it is Task Manager (Ctrl+Shift+Esc); on a Mac it is Activity Monitor. Open it while things are slow and sort by usage, and the cause is often obvious. Constantly high processor use means a program is calculating too much. Memory that is almost full means too much is open at once or there simply is not enough memory. Storage usage stuck near maximum may be updates, an antivirus scan, syncing, or the limits of a hard disk itself.
- High processor: quit or update that program
- Memory full: close tabs and programs, consider adding memory
- Storage always maxed: check background tasks, consider an SSD
Trim startup programs
Every program you install can add another item that launches automatically when the computer starts. Messengers, cloud sync and update checkers pile up, slowing boot and using resources the whole time the machine is on. In the startup list in Task Manager or system settings, turn off automatic launch for anything you do not need. Turning it off is not uninstalling; you can still open the program when you need it. But do not switch off items you cannot identify, especially those related to graphics, sound or input device drivers. Search for them first, then decide.
Free up storage
When storage is nearly full, the operating system has less room for temporary files and virtual memory, and updates are more likely to fail. The common advice is to always keep part of the capacity free. The storage page in system settings shows where the large files are. The Downloads folder, the recycle bin, old installers and duplicate photos and videos are the usual culprits. The built-in disk cleanup feature can remove temporary files safely. The file organisation guide goes into more detail.
Suspect heat and dust
A processor slows itself down to protect its parts when it gets too hot. So if dust blocks the vents, or you use a laptop on a duvet that covers the vents underneath, it slows noticeably regardless of its specs. If the fan is louder than usual or the case feels unusually hot, suspect heat. For dust around the vents, blowing it out from the outside with an air blower, with the power off and the charger unplugged, is a safe level of cleaning. Internal cleaning or replacing thermal material requires disassembly, so leave it to a service centre if you are not experienced.
Check the browser and updates
Much of the feeling that 'the computer is slow' is really the browser being slow. Dozens of open tabs or many extensions take up a lot of memory. Remove extensions you do not use, tidy up tabs, and keep the browser up to date. Operating system and driver updates also often fix performance and stability problems. On the other hand, right after a major update the system may be temporarily slow for a few days because of indexing and similar work, so waiting a little is also an option.
What not to do
The 'speed boost' and 'optimiser' programs advertised online have little real effect, and some stay running and use resources or install unwanted software alongside. Registry cleaning and similar tweaks make almost no noticeable difference and can cause problems if done wrong. SSDs do not need defragmenting; the operating system handles appropriate maintenance itself. Running two or more antivirus programs at once also causes conflicts and slowdowns.
- Installing optimiser or cleaner programs of unknown origin
- Editing the registry or system settings without good reason
- Running several antivirus programs at once
If it is still slow
If it is still slow after all this, the parts themselves may not be able to handle your workload. If you are on a hard disk, switching to an SSD is the upgrade you will feel most; if memory is always full, adding more is effective. Reinstalling the operating system is another option, but it erases everything, so back up first. If the slowdown came suddenly along with programs you do not recognise or a changed browser start page, suspect malware and follow the steps in the malware prevention guide. If the drive makes clicking sounds or error messages keep appearing, it may be about to fail, so back up immediately.
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