A slow Mac is usually caused by a resource bottleneck or a software issue. To fix a Mac that's running slowly, you should follow the right path — identify the causes first:
- Check whether the whole Mac, one app, the browser, or only websites are slow.
- Open Activity Monitor and review CPU, Memory Pressure, Energy, and disk activity.
- Check storage and remove only files that you are sure are unnecessary.
- Review Login Items, browser extensions, and apps that run in the background.
- Update macOS and apps.
- If the problem continues, test in Safe Mode or run Apple Diagnostics.
Do not delete files or upgrade memory until you have identified the cause and confirmed that the Mac model supports the change.
First, identify what is actually slow
The correct fix depends on the symptom. So, check what is slow on your Mac.
| What's slow on your Mac | What to do first |
| The entire Mac is slow — Apps, Finder, and menus all respond slowly | Open Activity Monitor and check CPU usage and Memory Pressure to identify resource bottlenecks. Go to System Settings > General > Storage to check the space usage. |
| Only one app is slow or freezes | Update the app, clear the app cache, and check for known compatibility issues. |
| Only your browser or websites are slow | Try another website or browser. Check browser extensions, network speed, DNS, and Wi-Fi before changing system files. |
| The Mac becomes slow after a macOS update | Allow time for indexing and background tasks to finish. Then check available storage, app compatibility, and update-specific troubleshooting steps. |
| Your Mac runs hot, or its fans are loud | Check CPU and Energy usage in Activity Monitor. A process using sustained CPU may be responsible. Avoid force-quitting system processes unless you know what they do. |
This separation prevents a slow website or Wi-Fi connection from being misdiagnosed as a failing Mac.
Use the all-in-one Mac cleaner to accelerate a slow Mac:
iBoysoft Cleaner is an AI-driven cleaning tool for Mac. It can troubleshoot most of the troublemakers that cause a Mac to run slowly.
It smartly scans your Mac and lists the system junk files by type for one-click deletion, including browser cache, temporary system files, system logs, application cache, Trash, and more.
Besides, it can:
- ✅ Analyze disk space usage with AI explanations, letting you know what to delete and what to keep.
- ✅ Find and delete large files and duplicate files, completely uninstall unwanted apps, and clean up leftovers of previously deleted apps to free up more space.
- ✅ Manage login items to accelerate a slow Mac startup due to apps and background processes that launch automatically at startup.
- ✅ Free up memory to fix frozen performance.
- ✅ Re-index Spotlight to fix a slow Mac caused by problematic macOS search.
- ✅ Refresh DNS to clear your Mac's cached DNS records to troubleshoot a slow browser or websites.
Steps to use iBoysoft Cleaner to optimize your Mac:
- Install and open iBoysoft Cleaner.
- Select a mode you want to try, such as System Junk, App Uninstaller, Large Files, and more.
- Wait for the scan to complete.
- Review every category, exclude files you need, and perform the corresponding action.
Notably, a cleanup tool cannot fix a slow Mac caused by CPU, thermal, network, or hardware problems.
1. Check Activity Monitor first
Activity Monitor shows which processes are using high CPU, memory, energy, and disk resources.
- Open Finder > Applications > Utilities > Activity Monitor.
- Select CPU and click the % CPU column to sort it.
Look for an app that stays unusually high while the Mac is slow. - Select Memory and review the Memory Pressure graph at the bottom of the window.
Also note Swap Used and whether the same app repeatedly consumes a large amount of memory. - Select Energy to find apps using significant energy, especially on a MacBook running on battery.
- Select Disk if Finder, file transfers, or launches are unusually slow.
If you need a separate benchmark, use a documented Mac disk speed test and compare results with the drive's expected interface and condition.
Memory Pressure is more useful than a simple RAM total. A green graph generally means macOS is managing memory efficiently; yellow or red indicates increasing memory pressure and should be investigated alongside the apps you are using. The exact display can vary by macOS version.
If one app is responsible, save your work, quit it normally, and check for an update. Do not routinely force-quit kernel_task or other system processes. If a process name is unfamiliar, search Apple's documentation or the software vendor's documentation before stopping it.
2. Check storage without relying on an arbitrary percentage
Low disk space can interfere with macOS updates and some apps or tasks that need extra room for temporary files and other data. There's no universal free-space threshold that determines when a Mac will slow down, but running critically low on storage can contribute to performance issues. Check how much storage is available and what's taking up space.
- On macOS Ventura or later, choose Apple menu > System Settings > General > Storage.
- On earlier macOS versions, choose Apple menu > About This Mac > Storage.
Step 1. Review the largest categories first.
Step 2. Empty the Trash only after confirming that you do not need the files.
Step 3. Remove old installers, duplicate media, and apps you recognize, or move large files to a trusted external drive or cloud service.
Note: Keep a backup before deleting anything important. Avoid deleting random files from system or Library folders.
Manually cleaning up the Mac is time-consuming. And mistakenly deleting system- or software-related files may affect system or software performance. So, we suggest you use a professional Mac cleaner instead, like iBoysoft Cleaner, to help you clean up the system junk fast and safely.
Powered by smart searching and cleanup, iBoysoft Cleaner can help you understand what to delete safely and what should remain.
3. Close unused apps, tabs, and extensions
Multiple apps and browser tabs can increase CPU and memory use. Close what you are not using, especially large creative apps, virtual machines, games, and browsers with many active tabs.
For browser-only slowness:
- Open a private window and test the same website.
- Temporarily disable extensions, then re-enable them one at a time to identify a problem extension.
- Test another browser and another network if possible.
- Update the browser and remove extensions that you don't recognize or no longer need.
If every browser is slow but other apps are responsive, investigate the network before changing Mac system settings. If the whole Mac is slow, return to Activity Monitor and check Memory Pressure.
4. Check Login Items and background activity
Apps that launch at login can delay startup and continue using resources in the background.
- On macOS Ventura or later, choose Apple menu > System Settings > General > Login Items.
- On earlier versions, open System Preferences > Users & Groups, select your user account, and open Login Items.
Remove only items you recognize and do not need at startup. Some security, backup, accessibility, and hardware utilities are expected to run in the background. If you are unsure, search the developer's documentation before removing an item.
The Allow in the Background list in modern macOS can also show background services. Disable a service only when you understand which app uses it and what feature you may lose.
5. Check for suspicious apps and malware indicators
An unfamiliar app, repeated pop-up, unexpected login item, or unexplained browser redirect deserves investigation.
Downloading software from outside the App Store is not automatically unsafe, but the source, developer identity, code signing, notarization, permissions, and current security status matter.
- Remove software only after identifying it and confirming that you do not need it.
- Review System Settings > Privacy & Security for unusual permissions and security warnings.
- Keep macOS and reputable security software updated.
- If a security alert appears, follow Apple's or the security vendor's documented removal steps.
Do not install a cleaner or security product solely because a pop-up says your Mac is infected. Close the page and verify the claim using a trusted source.
6. Update macOS and apps
An outdated app can conflict with a newer system, while an older Mac may not support the latest macOS. Check compatibility before upgrading.
- On macOS Ventura or later, choose Apple menu > System Settings > General > Software Update.
- On earlier versions, choose Apple menu > System Preferences > Software Update.
Install updates from the Apple App Store or Software Update. Back up important data before a major macOS upgrade, keep the Mac connected to power, and allow time for indexing or other background work after the update.
If the Mac became slow immediately after an update, record the macOS version, check whether the issue affects all apps, and follow this troubleshooting guide:
Mac running slow after an update
Do not downgrade or remove system files as a first step.
7. Use Safe Mode and Apple Diagnostics for persistent problems
If the Mac remains slow after the steps above, use a controlled test instead of repeatedly deleting files.
Safe Mode starts macOS with limited software and performs checks that can help identify startup software or cache-related issues. The steps differ between Apple Silicon and Intel Macs. Follow: How to Boot into Mac Safe Mode.
Apple Diagnostics can help identify possible hardware problems. Disconnect nonessential external devices and follow Apple's model-specific instructions.
Record the symptoms, the time they occur, the affected apps, and any Activity Monitor observations. That information is useful when contacting Apple Support or an authorized service provider.
8. Check RAM correctly before considering hardware service
Apple silicon Macs use unified memory that is generally selected at purchase and is not user-upgradeable. Some Intel Macs have upgradeable memory, while others do not. Check the exact model and Apple's repair or technical documentation before buying parts or opening the computer.
If Memory Pressure stays yellow or red during your normal workload, close or replace the app using the most memory, reduce simultaneous workloads, and check whether your model supports a serviceable memory upgrade. If it does not, consider an Apple-authorized service provider or a replacement decision based on your workload rather than a generic RAM threshold.
Note: Do not use "less than 4 GB of RAM can lag Mac's performance" as a universal rule. RAM is only one part of the diagnosis. Mac performance depends on the workload, macOS version, available storage, Memory Pressure, and the exact model.
FAQ
- QCan deleting files speed up the slow Mac?
-
A
A slow Mac is usually caused by a resource bottleneck, a software problem, or an issue limited to one app or network connection. First, identify what is slow. Start by blindly deleting files, as it may cause data loss and trigger improper app or system performance.
- QWhy is my Mac slow when it has plenty of storage?
-
A
Free storage is only one possible factor. Check Memory Pressure, CPU usage, Login Items, browser extensions, app compatibility, temperature, and recent updates. A Mac can have free storage and still be limited by memory pressure, a runaway process, a slow external drive, or a network problem.
- QWhy is my MacBook slow after an update?
-
A
Check the exact macOS version, available storage, app compatibility, and whether one process is using sustained CPU or memory. Allow background tasks to finish, restart once, and use the update-specific troubleshooting steps if the slowdown continues.
- QShould I upgrade my Mac's RAM?
-
A
Check Memory Pressure and the exact model first. Apple Silicon memory is generally not upgradeable after purchase, and Intel Mac upgradeability varies by model. And the slow Mac is not always caused by limited RAM.