Why your Windows PC feels slow, and what actually helps
Work out which part is slow before you change anything. The fix is usually one of five things, and several popular remedies do nothing at all.
By Hasnain Butt Akhtar, founder and developer ·
Slow means different things. A machine that takes four minutes to reach the desktop has a different problem from one that boots quickly and then stutters in the browser. Working out which kind of slow you have takes about two minutes and saves you from trying fixes that were never going to help.
Start by naming the problem
Ask yourself which of these matches your machine, because each one points somewhere different.
| What is slow | Usually means |
|---|---|
| Startup takes minutes, then it settles | Too many programs launching with Windows |
| Everything is slow, all the time | A mechanical hard drive, or a drive that is nearly full |
| Fine until you open a few things, then it crawls | Not enough memory |
| Only the browser is slow | Extensions, tabs, or the browser cache |
| Fast at first, slow after twenty minutes of load | Heat, and the machine reducing its own speed to cope |
Task Manager will confirm it. Press Ctrl, Shift and Escape together, then look at the Performance tab while the machine is being slow. Whichever of CPU, memory or disk is sitting near 100 per cent is your answer.
The five things that actually help
- Cut what starts with Windows. In Task Manager, open the Startup apps tab. It lists every program that launches at boot, with a rating of how much it costs you. Anything marked High impact that you do not need immediately can be disabled. Chat apps, game launchers, updaters and printer utilities are the usual offenders. Disabling here does not uninstall anything, and you can still open the program normally afterwards.
- Give the drive room to breathe. A solid state drive slows down noticeably when it gets close to full, because it needs spare space to shuffle data around. Aim to keep at least 10 to 15 per cent free. If your system drive is showing red in File Explorer, this alone may be your whole problem.
- Check what kind of drive you have. In Task Manager, under Performance, your drives are listed with their type. If it says HDD, you have a mechanical disk, and replacing it with an SSD will transform the machine more than any other single change. Nothing you do in software comes close. On an older laptop this is often the difference between replacing the machine and keeping it for another three years.
- See whether you are short of memory. In Task Manager, under Performance, select Memory and use the machine normally for a while. If it sits above about 80 per cent during ordinary work, Windows is constantly moving things to disk to cope, and everything feels sluggish as a result. More memory is a cheap fix on a desktop and often possible on a laptop.
- Update the graphics and chipset drivers. Windows Update handles most drivers, but it often supplies an older graphics driver than the manufacturer offers. If display, video or games feel wrong, get the driver directly from AMD, Intel or NVIDIA. This fixes stutter that no amount of cleaning will touch.
When it is heat, not software
If your machine is quick from cold and slows down after twenty minutes of real work, particularly if the fan is loud, the problem is temperature. Processors deliberately reduce their own speed when they get too hot, which protects the hardware and costs you performance.
On a laptop the cause is almost always blocked airflow. Dust in the vents, or using it on a bed or a sofa where the intakes are covered. Compressed air through the vents and a hard flat surface fixes a surprising number of these. On an older machine the thermal paste between the processor and its cooler dries out over several years, and replacing it is a job worth paying for if the machine is otherwise good.
You can confirm it before spending anything. Watch the CPU speed in Task Manager under Performance while the machine is being slow. If the clock speed drops well below the rated figure while the load is high, the machine is protecting itself from heat.
What does not help
| Common advice | Why it does not work |
|---|---|
| Registry cleaning | Registry size has no measurable effect on speed, and removing entries can break working software |
| Memory optimisers and RAM boosters | They force Windows to discard cached data it deliberately kept, which usually makes things slower |
| Defragmenting an SSD | Solid state drives do not benefit from it, and Windows already maintains them correctly on its own |
| Disabling services from a list found online | Saves a few megabytes at best, and breaks features in ways that surface weeks later |
| Turning off the page file | Some programs rely on it. If the drive is short of room, move it rather than removing it. |
The smaller adjustments worth making
Once the five main causes are dealt with, these are worth a few minutes each.
Browser extensions. Every extension runs on every page. If browsing specifically is slow, disable them all, confirm the browser is quick again, then re-enable them one at a time. The culprit usually announces itself within a couple of minutes.
Power settings. On a desktop, check that you are not on a power saving plan. On a laptop running on battery, reduced performance is intentional, so compare like with like by testing while plugged in.
Visual effects. On older hardware, setting Windows to adjust for best performance in the advanced system settings gives a modest but genuine improvement in how responsive the interface feels. On a modern machine it makes no real difference and simply looks worse.
A malware scan. Worth doing once, with the built in Windows Security, before you conclude it is a hardware problem. Something using your processor in the background looks exactly like a slow computer.
If you work through all of this and the machine is still slow, the honest answer may be that it is old. A processor from ten years ago is slower than a current one at everything, and no amount of tuning changes that. Knowing you have ruled out the fixable causes is still worth the twenty minutes, because it turns a vague frustration into a clear decision about whether to upgrade.