How to Speed Up Windows 11

Most Windows slowdowns are not mysterious. A PC that took 20 seconds to reach the desktop and now takes two minutes has usually accumulated startup programs, run out of disk headroom, or both. This guide works through the causes in the order that actually pays off, and is honest about which popular tips do nothing.

First, find out what is actually slow

"Slow" covers several different problems with different fixes, so spend two minutes identifying which one you have before changing anything.

Open Task Manager with Ctrl + Shift + Esc and look at the Performance tab while the machine feels slow.

What you see	Likely cause	Go to
Disk pinned at 100%	Too little free space, a mechanical drive, or a background indexer	Steps 2 and 3
Memory near 100%	Too many programs, or genuinely not enough RAM	Steps 1 and 6
CPU high with nothing open	Startup and background apps	Step 1
Slow only at boot	Startup programs	Step 1
Everything fine, one app slow	That app, not Windows	Step 7

The Startup apps tab in the same window gives each program a startup impact rating. That is the single most useful screen in Windows for this problem.

Step 1: cut what starts with Windows

This is almost always the biggest win, and it is completely reversible.

Go to Settings > Apps > Startup, or open the Startup apps tab in Task Manager. Turn off anything you do not need running from the moment you log in.

To see the full list including entries that Settings hides, run this in PowerShell:

Get-CimInstance Win32_StartupCommand | Select-Object Name, Command, Location

On the machine I checked while writing this, that returned 21 startup entries — cloud storage clients, a game launcher, a chat app and a local AI runtime among them. None of those need to be running before the user has asked for them.

Safe to disable: chat clients, game launchers, music and streaming apps, update helpers for software you rarely use, printer and scanner utilities, "quick start" companions for creative suites, cloud drive clients you sync manually.

Leave alone: anything from your antivirus, touchpad or graphics drivers, and OneDrive if you genuinely rely on live file sync.

Disabling a startup entry does not uninstall the program. It just stops it launching itself; you can still open it normally, and you can switch it back on in the same screen.

Step 2: give the system drive room to breathe

Windows needs free space on C: for the page file, temporary files and updates. When the system drive fills past roughly 90%, performance degrades noticeably — and on the machine I checked while writing this, C: had 28.4 GB free out of 487 GB, which is under 6%. That alone is enough to make a fast PC feel sluggish.

Check yours in PowerShell:

Get-PSDrive C | ForEach-Object {
  "{0} GB free of {1} GB" -f [math]::Round($_.Free/1GB,1), [math]::Round(($_.Free+$_.Used)/1GB,1)
}

Aim for at least 15–20% free, or 50 GB, whichever is larger. (If you want the figure for your own drive, our percentage calculator will tell you what 15% of it comes to.) To reclaim space:

• Settings > System > Storage shows what is using the drive, broken down by category. Start with the biggest bar, not the easiest one.
• Temporary files in that same screen safely clears update leftovers, delivery optimisation files and thumbnail caches. This is where the old Disk Cleanup tool's function now lives.
• Storage Sense (Settings > System > Storage > Storage Sense) automates the cleanup on a schedule so you do not have to remember.
• Previous Windows installation — after a feature update, a Windows.old folder can hold 20 GB or more. It exists so you can roll back, and Windows deletes it automatically after 10 days. If you are sure you do not need to roll back, clearing it in the Temporary files screen is usually the single largest recovery available.
• Downloads is the folder people forget. Installers you ran once are still there.

If you want to understand the units involved — why a "1 TB" drive shows as 931 GB in Windows — our guide to MB, GB and TB explained covers the base-1000 versus base-1024 difference that causes it.

Step 3: find out whether you have an SSD or a hard disk

This is the step most guides skip, and it determines whether any of the others will help much. A mechanical hard disk is the single most common reason a Windows 11 machine feels slow no matter what you do — random reads are hundreds of times slower than on an SSD, and Windows 11 does a lot of small random reads.

Open Task Manager > Performance and select the disk; the type is listed. Or in PowerShell:

Get-PhysicalDisk | Select-Object FriendlyName, MediaType, Size

If MediaType says HDD, no amount of software tuning will fix the underlying problem. Replacing it with an SSD is the only upgrade that reliably transforms an old machine, and it usually matters more than adding RAM or changing the CPU.

One important consequence: do not defragment an SSD. Windows already handles SSD maintenance correctly by running TRIM instead, and the Optimize Drives tool knows the difference. Third-party "defrag your SSD for speed" tools are at best pointless and at worst shorten the drive's life. Defragmenting is only meaningful on mechanical drives.

Step 4: set the power plan to match the machine

Laptops ship on a balanced profile that trades speed for battery, which is sensible on battery and wasteful when plugged in.

List your available plans:

powercfg /list

On the machine I checked, that returned three: Balanced (active), High performance, and Power saver. To switch to High performance, pass its GUID to /setactive:

powercfg /setactive 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c

Those GUIDs are the standard Windows ones and are the same across machines. You can also do it without the command line in Settings > System > Power & battery > Power mode. On a desktop there is no real reason not to run the higher setting; on a laptop expect shorter battery life.

Step 5: turn off the animations

This does not make the computer faster, but it makes it feel faster, which is often what people actually want. Windows animates window transitions by a couple of hundred milliseconds each; removing that delay makes the interface respond instantly.

Go to Settings > Accessibility > Visual effects and turn off Animation effects. Transparency effects are in the same screen and cost a little GPU work.

For finer control, press Windows + R and run sysdm.cpl, then Advanced > Performance > Settings. "Adjust for best performance" disables everything at once, which looks stark; unchecking just the animation boxes keeps the interface pleasant and removes the waiting.

Step 6: check whether you are simply out of RAM

In Task Manager's Performance tab, look at memory composition rather than the headline percentage. Windows deliberately uses free RAM for caching, so high usage is not itself a problem. What matters is whether the machine is paging to disk.

If the "Committed" figure regularly exceeds your physical RAM, the system is swapping and everything slows down at once. 8 GB is workable for browsing and documents; 16 GB is the comfortable floor for a machine running a browser with many tabs alongside other applications.

Before buying RAM, check what is consuming it in the Processes tab, sorted by memory. Browsers are usually top, and a browser with 60 tabs open is an application problem rather than a hardware one.

Step 7: repair Windows itself

If the machine became slow suddenly rather than gradually, corrupted system files are worth ruling out. Open Terminal or Command Prompt as administrator and run:

sfc /scannow

If it reports problems it could not fix, follow with:

DISM /Online /Cleanup-Image /RestoreHealth

Then run sfc /scannow again. DISM repairs the component store that SFC draws its replacement files from, which is why the order matters. Both tools ship with Windows — sfc.exe and Dism.exe both live in C:\Windows\System32 — and neither touches your personal files. Expect the pair to take 15–30 minutes.

Microsoft documents both: the System File Checker reference lists every switch, and the guide to repairing a Windows image explains what RestoreHealth is actually doing.

What does not work

Several popular suggestions are ineffective, and a few are actively harmful.

Common advice	Reality
Registry cleaners	No measurable speed benefit. Microsoft does not support them, and a bad clean can prevent booting.
"RAM booster" utilities	They force data out of a cache Windows was managing deliberately, so the next read is slower.
Defragmenting an SSD	Unnecessary and adds write wear. Windows runs TRIM instead.
Disabling the page file	Causes out-of-memory crashes in programs that expect it to exist.
Turning off Windows Update	Trades a small, occasional slowdown for an open security hole.
Ending random background processes	Most are parts of Windows. Stopping them causes instability, not speed.

If a tool promises to make Windows dramatically faster with one click, the honest version of what it does is contained in steps 1 and 2 above, which are free.

A realistic order of operations

1. Check Task Manager to identify which resource is saturated (2 minutes).
2. Disable unnecessary startup apps (5 minutes, biggest typical win).
3. Free disk space until at least 15% is available (10–30 minutes).
4. Confirm SSD or HDD — this sets your expectations for everything else (1 minute).
5. Set the power plan (1 minute).
6. Turn off animations if the interface feels laggy (1 minute).
7. Run SFC and DISM if the slowdown was sudden (30 minutes, mostly waiting).

If you have done all seven and the machine is still slow, and step 3 said HDD, you have your answer. If it said SSD and the machine still struggles, the bottleneck is most likely RAM or a specific misbehaving application rather than Windows.

Worth separating out: if the machine is fine but websites feel slow, that is a different problem with different causes — our notes on why a site loads slowly cover that side of it.

Frequently asked questions

Why is my Windows 11 PC so slow all of a sudden?

A sudden slowdown usually means one of three things: the system drive has filled up, a recently installed program added itself to startup and background services, or system files were corrupted. Check free space on C: first, then the Startup apps tab in Task Manager, then run sfc /scannow if neither explains it.

Does disabling startup programs delete them?

No. It only stops them launching automatically when you sign in. The programs stay installed and open normally, and you can re-enable automatic startup at any time in Settings > Apps > Startup.

How much free disk space does Windows 11 need?

Aim for at least 15–20% of the drive free, or about 50 GB, whichever is larger. Windows uses that headroom for the page file, temporary files and updates. Performance degrades noticeably once the system drive passes roughly 90% full.

Should I defragment my SSD to speed it up?

No. SSDs have no moving parts and no seek penalty, so defragmentation gains nothing and adds unnecessary writes. Windows automatically runs TRIM on SSDs instead, and the built-in Optimize Drives tool detects the drive type and does the right thing.

Do registry cleaners make Windows faster?

No. There is no measurable performance benefit from removing unused registry entries, Microsoft does not support these tools, and an aggressive clean can remove entries Windows needs to boot. Free disk space and reduce startup programs instead.

Is it worth adding RAM or replacing the drive first?

Replace the drive first if it is a mechanical hard disk — moving to an SSD is the single largest improvement available on an older machine. If you already have an SSD and the Committed memory figure in Task Manager regularly exceeds your installed RAM, more memory is the next step.

Conclusion

Windows 11 rarely slows down for no reason. In almost every case it is startup programs stealing the first two minutes after login, a system drive with no room left to work in, or a mechanical hard disk that was never fast enough for the job.

Work through the first three steps and you will have addressed the cause on most machines. The rest of this list is refinement — and the tools promising a one-click fix are, at best, doing steps 1 and 2 for you.