Find the bottleneck before changing anything
A computer feels slow when one resource runs out: the processor is busy, memory is full, the drive is struggling, or the network is slow. Guessing which one wastes effort. Open the built-in monitoring tool, which is Task Manager on Windows (press Ctrl+Shift+Esc) or Activity Monitor on macOS, and look at the columns for processor, memory and disk.
Sort by each column in turn. If one program uses a large share of something while you are not even working in it, you have found a lead. If everything looks calm and the machine is still slow, the cause may be elsewhere, such as a web page, a network problem or ageing hardware.
Trim what starts with the computer
Programs that launch at sign-in slow the first minutes after startup and then keep using memory all day. Many installers add themselves without asking.
- Windows: in Task Manager, open the Startup tab. It lists each item and an estimate of its impact. Right-click and choose Disable for things you do not need running immediately, such as chat apps, updaters for rarely used software and extras bundled with printers.
- macOS: open System Settings, then General, then Login Items, and remove or switch off items you do not need.
Disabling a startup entry does not uninstall the program; you can still open it by hand. If you do not recognise an entry, search for its exact name before changing it, and leave security software and drivers alone.
Close background work you do not need
The same monitor shows what is running now. Quit programs you are not using instead of leaving them open for days. Some are less obvious: cloud sync tools, game launchers and video apps can keep working in the background. You do not have to remove them, but pausing file syncing during a heavy task can free up resources.
A regular restart is also worth the minute it takes. Restarting clears memory, ends stuck processes and finishes pending updates. Machines left running for weeks sometimes accumulate problems that a restart fixes.
Keep the browser lean
For many people the browser is where most of the work happens, and it can use a surprising amount of memory. Each open tab and each add-on takes a share.
- Close tabs you are not using, or use the browser’s built-in feature that puts inactive tabs to sleep, if it has one.
- Review your extensions and remove any you do not use. Every browser extension runs code in the background, and a large collection can slow page loads. Keep the ones you trust and need.
- Check that the browser itself is up to date.
Free some drive space
Drives with very little room left tend to slow everything down. Clearing the bin, removing unused applications and moving large media to an external drive all help. Finding what fills a drive is covered in the guide on disk space, so this article only notes that low free space is one of the more common causes of sluggishness. The built-in disk cleanup tools are fine for temporary files; avoid third-party “optimizer” programs that promise dramatic results.
Keep the system updated
Updates to the operating system, drivers and applications sometimes include performance fixes as well as security ones. Install them when prompted and restart afterward. If a machine has been ignoring updates for a long time, expect the first round to take a while.
Check for unwanted software
If a computer slowed down suddenly and you see strange programs, a browser home page you did not choose or pop-ups, unwanted software may be involved. Run the scan built into your operating system’s security tools, and uninstall programs you do not recognise. Be wary of pop-ups that claim your computer is infected and urge you to call a number or buy a cleaner; these are a known pattern in tech support scams, and a real warning from your own security software will not ask you to phone anyone.
Power and heat settings
On a laptop, power modes can trade speed for battery life. If the computer is plugged in and feels slow, check that it is not set to the most power-saving mode. Heat also slows machines, because processors reduce their speed when they get too hot. Make sure vents are not blocked, avoid using a laptop on a soft surface such as a bed, and, if you are comfortable doing so or have someone who is, clearing dust from fans can help on desktops. Heat and charging habits are discussed more in the article on laptop batteries.
When software tweaks stop helping
Tuning has limits. If the monitor shows memory consistently near full, adding random access memory, if the machine allows it, is often the most effective single upgrade. If the computer still uses a spinning hard drive, replacing it with a solid state drive is commonly the largest improvement a user can notice for the price. A very old processor, or one that cannot run current software well, may mean it is time to replace the machine, and how to choose computer hardware has its own guide.
Slowness that appears only online may not be the computer at all. A slow connection can make a healthy machine look sluggish, which is why checking Wi-Fi speed on its own is worthwhile before blaming the computer.
A short routine
- Open the task manager and note what is using the most resources.
- Disable startup items you do not need.
- Quit unused programs and tabs, and remove unneeded extensions.
- Check free drive space and clear what you safely can.
- Install pending updates and restart.
- Scan for unwanted software if the slowdown was sudden.
Change one thing at a time so you can tell what helped, and keep a copy of important files before making bigger changes. Results vary from machine to machine, and an older computer may only improve modestly.