Laptop Running Slow? How to Find Out What's Causing It (Windows 11)

Your laptop used to run smoothly, but now even simple tasks seem to take forever. Applications are slow to open, browser tabs hang, Windows takes minutes to start or the computer periodically freezes.

A slow laptop doesn't necessarily mean you need a new one. The important thing is to identify what is slowing it down before applying a fix.

Common causes include:

• Too many applications running in the background.
• High CPU or memory usage.
• Slow or saturated storage.
• Insufficient free disk space.
• Unnecessary startup apps.
• Windows updates or background maintenance.
• Overheating and thermal throttling.
• Malware or unwanted software.
• Aging or insufficient hardware.

This guide focuses on Windows 11, although many checks also apply to Windows 10.

Quick troubleshooting checklist#

If you're short on time, use this table to decide where to start.

Step 1 — Restart Windows#

Select Start → Power → Restart.

A proper restart ends running processes and allows some pending Windows updates to finish. Wait a few minutes after signing in for normal startup tasks to settle, then see whether performance improves.

If the issue returns, investigate further rather than repeatedly restarting.

Step 2 — Check CPU, memory and disk usage#

Press:

Ctrl + Shift + Esc

This opens Task Manager.

Select Processes, then sort by CPU, Memory or Disk by clicking the relevant column heading.

Short spikes are normal—for example, CPU usage rising briefly when launching software. Sustained heavy usage while the system should be idle is more interesting.

Find the responsible process#

If CPU usage remains high, sort the CPU column and note the process at the top.

Typical causes include:

• Browsers with many tabs.
• Antivirus scans.
• Windows Update.
• Cloud backup or synchronisation tools.
• Games and creative applications.
• Processes repeatedly crashing or retrying.

Don't immediately end unfamiliar Windows processes. Find out what they do first.

What if memory usage is high?#

Sort the Memory column and close unnecessary applications or browser tabs. If you routinely exhaust the installed RAM, an upgrade may help—if the laptop supports it.

Step 3 — Get more detail with Resource Monitor#

Press Windows + R and run:

resmon

Resource Monitor has tabs for CPU, Memory, Disk and Network.

Disk tab#

Look at processes generating read/write activity and the files they're accessing. Check disk active time and response times.

If the laptop freezes while the drive shows high active time and long response times, storage may be involved. However, high activity alone does not prove that a drive is failing; Windows updates or antivirus scans can also saturate a healthy drive.

Memory tab#

Inspect available RAM and Hard Faults/sec. A hard fault happens when Windows must retrieve a memory page from storage rather than physical RAM.

Some hard faults are normal. Sustained paging, low available memory and visible slowdowns together suggest memory pressure.

Step 4 — Review startup applications#

Open Task Manager → Startup apps.

Sort by Startup impact and review applications configured to launch automatically.

Common candidates include gaming launchers, messaging apps, unused manufacturer utilities and cloud-sync clients you don't need immediately.

To disable unnecessary automatic startup:

1. Right-click the application.
2. Select Disable.
3. Restart later and compare startup responsiveness.

This normally disables automatic launch without uninstalling the program.

Do not randomly disable antivirus software, device services, drivers or organisation-managed tools.

Step 5 — Check available disk space#

Open:

Settings → System → Storage

Check the free space on your Windows drive, normally C:.

From PowerShell:

Get-Volume -DriveLetter C |
  Select-Object DriveLetter, SizeRemaining, Size

There is no single free-space percentage at which every PC becomes slow. As a practical diagnostic guideline, investigate if less than roughly 10–15% of the system drive remains free.

To reclaim space safely, visit Settings → System → Storage → Temporary files and review the available options. Pay attention before deleting Downloads, Recycle Bin contents or previous Windows installations.

Storage Sense can help automate appropriate clean-up tasks.

Avoid third-party registry cleaners or one-click PC optimisation applications.

Step 6 — Check whether Windows is installed on an HDD or SSD#

Storage type can make a major difference to everyday responsiveness.

Mechanical hard drives (HDDs) have much higher access latency than SSDs, which affects boot times, app launches and multitasking when the system is accessing many small files.

Check Task Manager → Performance → Disk for the drive type, or run:

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

Example:

FriendlyName      MediaType   HealthStatus   Size
------------      ---------   ------------   ----
Example SSD       SSD         Healthy        512 GB

If Windows runs from an old HDD, replacing it with a compatible SSD often makes a large difference. Check the manufacturer's upgrade options and back up the machine first.

Step 7 — Check the health of the storage drive#

Possible warning signs include:

• Unexpected freezes during file operations.
• Files that take unusually long to open.
• File-system corruption or repeated disk errors.
• Manufacturer SMART/health warnings.
• Clicking or grinding noises from a mechanical HDD.

Run:

Get-PhysicalDisk |
  Select-Object FriendlyName, HealthStatus, OperationalStatus

For additional counters where supported:

Get-PhysicalDisk | Get-StorageReliabilityCounter |
  Select-Object DeviceId, Temperature, Wear, ReadErrorsTotal, WriteErrorsTotal

Some drives and controllers do not expose these fields. Missing counters or a Healthy status do not prove a drive is fault-free.

For deeper checks, use the laptop or drive manufacturer's official diagnostics.

If you suspect a failing drive, back up your important files immediately. Avoid repeatedly running intensive repairs or scans on potentially failing hardware.

Step 8 — Look for overheating and thermal throttling#

A processor may reduce its clock speed to control temperature. This is called thermal throttling.

Possible symptoms:

• Fans running loudly all the time.
• A very hot chassis.
• Good performance initially, then slow performance under load.
• Reduced performance during gaming or intensive work.

Open Task Manager → Performance → CPU and observe speed during the slowdown. Remember that modern processors change frequency dynamically; a speed below the displayed base speed alone is not proof of throttling.

A reputable monitoring utility or the laptop manufacturer's diagnostics can help confirm elevated temperatures and throttling.

Practical checks:

1. Place the laptop on a flat, hard surface.
2. Keep ventilation openings clear.
3. Remove dust from accessible vents.
4. Check that the cooling fan works.
5. Avoid blocking airflow with blankets or soft furnishings.

Internal cleaning or thermal maintenance may be needed on older hardware. Consider electrical/battery safety and warranties before opening a laptop.

Step 9 — Check Windows power settings#

Open:

Settings → System → Power & battery → Power mode

Depending on the laptop, you may see Best power efficiency, Balanced or Best performance.

Connect the laptop to the charger and test Best performance to see whether power limits contribute to the issue.

Manufacturer control software may impose additional profiles. Best performance may increase noise, heat and power consumption; it is not always the right permanent choice.

Step 10 — Scan for malware and unwanted software#

Open:

Windows Security → Virus & threat protection → Quick scan

If you see suspicious behaviour, consider a full scan.

Warning signs include unknown background programs, browser redirects, unexpected extensions and security protection being disabled.

Keep Microsoft Defender—or your organisation's approved security product—enabled. Installing multiple real-time antivirus engines usually creates more complications than benefits.

Step 11 — Check Windows updates and drivers#

Navigate to Settings → Windows Update → Check for updates.

Install relevant security and reliability fixes. Under Advanced options → Optional updates, review any available drivers based on the problem you're investigating.

For chipset, storage, GPU and firmware updates, prefer the laptop manufacturer's official support site. Avoid unknown driver-updater utilities.

If a slowdown began immediately after a driver update, investigate an appropriate driver rollback.

Step 12 — Check Reliability Monitor#

Press Windows + R and run:

perfmon /rel

Reliability Monitor provides a timeline of recorded application failures, Windows failures, hardware events and installations.

Look for events appearing around the time performance worsened:

• Repeated crashes.
• Failed updates.
• Hardware errors.
• Software installations.

Opening an event may reveal an application or driver that started failing repeatedly. This is especially helpful when the slowdown began suddenly.

Step 13 — Check for Windows system-file corruption#

Use DISM and SFC when you have evidence of servicing corruption, failed repairs or recurring system errors—not as generic performance boosters.

Open Command Prompt as Administrator:

DISM /Online /Cleanup-Image /RestoreHealth

After DISM completes:

sfc /scannow

DISM repairs Windows servicing components; SFC checks protected system files.

Neither command will solve a laptop that is slow because of an aging HDD, insufficient memory or an overheating processor.

Step 14 — Decide whether hardware is the bottleneck#

Review Task Manager → Performance for CPU, RAM and storage details.

These are broad guidelines, not strict requirements.

Upgrade decisions should follow the measured bottleneck:

• If Windows boots from an HDD, a compatible SSD upgrade is often the most noticeable improvement.
• If RAM remains exhausted during your usual workload, more memory may help.
• If the CPU is continuously saturated, extra RAM or a faster SSD may have limited effect.

Check specifications first: many modern laptops have soldered memory or limited upgrade options.

What NOT to do#

• Don't use registry cleaners. They're not required for routine Windows performance maintenance.
• Don't disable random Windows services. You may break updates or essential security features.
• Don't delete files from Windows system directories by guesswork. Use built-in Storage settings.
• Don't run unknown “optimisation” scripts. They may weaken security or alter essential configuration.
• Don't reinstall Windows as your first action. Identify the cause and try targeted fixes first.
• Don't assume high disk or CPU usage means failing hardware. Background maintenance can legitimately use resources.

Summary#

If your laptop is slow, start by measuring rather than guessing:

1. Restart Windows and retest.
2. Inspect CPU, RAM, disk and process usage.
3. Use Resource Monitor to identify the activity.
4. Reduce unnecessary startup tasks.
5. Check free storage and whether you're running from an HDD or SSD.
6. Investigate disk health and overheating.
7. Check power settings, malware, updates and drivers.
8. Use Reliability Monitor for recent crashes and failures.
9. Consider hardware upgrades only when the evidence supports them.

The objective isn't a temporary speed boost—it's identifying and fixing the actual bottleneck.

References#

• Microsoft — Tips to improve PC performance in Windows
• Microsoft — Device performance and health
• Microsoft — Free up drive space in Windows
• Microsoft — Get-PhysicalDisk
• Microsoft — PC Health Check