A slow, cluttered Windows PC usually comes down to a few things you can fix quickly: too many apps launching at startup, a nearly full system drive, power settings that hold back your CPU and a browser full of open tabs. Work through the steps below and you can get most of your speed back without reinstalling anything. If your PC still lags afterward, an SSD or RAM upgrade is the next thing to look at.
Why a Windows PC slows down over time
Clutter builds up slowly. Old downloads, leftover update files and settings you haven’t touched in months pile up in the background. Each new app you install can also add itself to the startup list, so it launches every time you restart and sits in your system tray. Each item has a small effect, but together they make your PC slower.
Turn off startup apps you don’t need
Startup apps can have a big effect on how fast your PC runs. Keep the few work apps you need right away and turn off the rest.
- Right-click the Start button and choose Task Manager.
- In the left pane, open the Startup apps tab.
- Click the Status column to sort apps by whether they’re enabled or disabled.
- Check the Startup impact column for apps marked high or moderate impact.
- Right-click each high or moderate impact app you don’t need at startup and disable it.
- Disable anything else that isn’t part of the apps you use for work.
Free up space on your Windows drive
Windows needs at least 15% free space on the drive it’s installed on to run efficiently, though the exact amount depends on the drive’s capacity. If your drive is nearly full, start with the built-in tools.
- Open the built-in Disk Cleanup tool.
- Select old Windows updates, antivirus definitions, temporary internet files and the Recycle Bin, then remove them.
- Set up Storage Sense so Windows clears this kind of clutter for you automatically from now on.
If you still need more room after that, install TreeSize. It gives you a visual map of what’s using your storage, so you can find the largest files and decide what to delete.
Change your power mode to Best performance
Windows has three power modes: Balanced, Best performance and Best power efficiency. On a laptop, Windows usually uses Balanced when plugged in and Best power efficiency on battery. These defaults save power and battery life, but they can throttle your CPU speed, which means Windows deliberately runs the processor slower.
- Go to Start > Settings > System > Power & battery.
- Expand the Power mode section.
- In the Plugged in drop-down menu, select Best performance.
- If you don’t want Windows to throttle performance on battery, select Best performance in the On battery drop-down menu as well.
Expect shorter battery life if you change the On battery setting.
Lower the Energy Saver threshold
Energy Saver turns on when your battery drops to a set percentage and cuts performance to save power. By default, it kicks in at 30%.
- Stay on the Power & battery page and find the Energy Saver settings.
- Change the battery percentage that turns Energy Saver on from 30% to 20% or 10%.
With a lower threshold, your laptop keeps running at full speed for longer before it starts throttling to save battery.
Cut down on open browser tabs
Keeping dozens of tabs open in case you need them later is easy to fall into. It clutters your workspace, and every tab uses memory, which can slow down your browser and the other apps running alongside it.
- Save tabs instead of keeping them open. An extension such as Session Buddy saves your open tabs as a collection you can restore later. Microsoft Edge’s Collections used to do something similar, but it no longer lets you add all open tabs to a collection at once.
- Set yourself a tab limit. Try to keep fewer than 10 tabs open at a time.
- Review tabs at the end of each session. Close anything you no longer need.
- Write down links instead of keeping them open. The Sticky Notes app is a quick place to save notes and links you want to come back to later that day.
Upgrade to an SSD or add more RAM
If your PC still lags after cleanup, the hardware may be the problem. Storage and memory are the two easiest parts to replace, and they’re often the main reason a system feels slow.
If you still use a conventional hard disk drive (HDD) for your main or secondary storage, moving to an NVMe or SATA SSD can make your PC much faster and reduce high disk usage. You’ll notice the difference in games too.
For memory, 16GB of RAM is now standard on modern desktops and laptops. That’s enough headroom for multitasking, even if you mostly browse the web with lots of tabs open. If you have 8GB, adding another 8GB RAM module is a cheap upgrade that can make a noticeable difference.
On many laptops, upgrading means removing the back panel and inserting the NVMe drive and RAM into their slots. The hardest part is often keeping track of the tiny screws. Not every laptop can be upgraded this way, so check with your manufacturer before you open your device.
Do a clean install for major Windows versions
When a major new version of Windows comes out, consider skipping the in-place upgrade and doing a clean install instead. It can save you problems later on.
Frequently asked questions
How much free space does Windows need to run well?
Windows needs at least 15% free space on its installation drive to run efficiently, though the exact amount depends on the drive’s capacity.
When does Energy Saver turn on by default?
Energy Saver turns on at 30% battery by default and reduces performance. You can lower it to 20% or 10% to keep full performance for longer.
How much RAM does a Windows PC need?
16GB is the standard for modern desktops and laptops and gives you enough headroom for multitasking. Adding an 8GB RAM module is a cheap upgrade.
Can I upgrade the SSD and RAM in any laptop?
No. Many laptops let you swap parts after removing the back panel, but not all of them. Check with your manufacturer before opening yours.
