Why Is My Computer So Slow? How to Fix It

7 min read  ·  Works on Windows 10, Windows 11, and macOS

A slow computer is one of the most frustrating tech problems — and one of the most common. The good news: most slowdowns are caused by fixable software issues, not hardware failure. These steps work on both Windows PCs and Macs, and most of them take less than 5 minutes each.

The Most Common Causes

Before fixing it, it helps to know why computers slow down. The usual culprits are: too many programs starting automatically when you turn on your computer, a nearly full hard drive, malware running in the background, an outdated operating system, or simply not enough RAM for what you're trying to do. We'll tackle each one.

Step-by-Step Fix

1

Restart your computer (properly)

This sounds obvious, but many people just close the lid or put it to sleep. A full restart clears the memory and closes background processes. On Windows, click Start › Power › Restart. On Mac, click the Apple menu › Restart. Wait for it to fully start up before testing speed.

2

Stop programs from starting automatically

Windows: Right-click the taskbar at the bottom, choose Task Manager, then click the Startup tab. Right-click anything you don't need and select Disable. Mac: Go to System Settings › General › Login Items and remove anything unnecessary.

3

Free up disk space

When your hard drive is more than 85% full, your computer slows down significantly. Windows: Open File Explorer, right-click your C: drive, and select Properties › Disk Cleanup. Mac: Click the Apple menu › System Settings › General › Storage to see what's taking up space and remove it.

4

Scan for malware

Malware running in the background is a major cause of slowdowns. Windows: Open Windows Security from the Start menu and run a Quick Scan. It's built in and free. Mac: Malwarebytes for Mac has a free version that's excellent for one-time scans.

5

Clean up your web browser

Browser extensions are a hidden cause of slowdowns. Open your browser's extensions or add-ons page and remove anything you don't actively use. Also clear your browser's cache: in Chrome, go to Settings › Privacy and Security › Clear browsing data.

6

Install all pending updates

Windows: Go to Settings › Windows Update and install anything available. Mac: Go to System Settings › General › Software Update. Updates often include performance improvements and security patches that can dramatically speed things up.

Quick check: Open Task Manager (Windows) or Activity Monitor (Mac) and look at what's using the most CPU and Memory. If a single app is using 80%+ of your CPU, that's your culprit — try force-quitting it.

When It Might Be Hardware

If you've tried all of these and your computer is still slow, the issue might be hardware. A computer older than 6–7 years with less than 8GB of RAM will struggle with modern software. Upgrading to an SSD (solid-state drive) is the single most effective hardware upgrade for a slow computer — it can make an old machine feel brand new. If your computer is very old, it may simply be time for a new one.

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