Why is my computer slow and the fans loud all the time?

Your computer may be slow and noisy because something is keeping its processor busy, making it produce heat that the fans must remove. If you are mining Monero in your browser, that can explain both symptoms—but if they continue after you stop mining, check for other busy apps, unwanted software, or a cooling problem.

Why mining makes your fans work harder

Your CPU, the main processor inside your computer, does calculations for the apps you use. Monero mining gives it a steady stream of demanding work through RandomX, Monero’s mining method, which favors CPUs.

That extra work can cause:

• Loud fans: Your cooling system speeds up to remove heat.
• Slower apps: Mining competes with your other tasks for processing power and memory.
• More heat and power use: A laptop may feel warmer and drain its battery faster.
• Reduced speed: If the processor gets too hot, it slows itself down to protect against overheating. This is called thermal throttling.

Constant fan noise is not proof of malware. But mining should happen only with your clear permission, and you should be able to stop it.

Check what is keeping your computer busy

First, use the mining page’s stop or pause control. Then close that tab. If nothing changes, fully quit the browser, including any background browser processes, and give the computer a few minutes to cool down.

Next, check what is using your resources:

• Windows: Open Task Manager with Ctrl + Shift + Esc.
• Mac: Open Activity Monitor from Applications → Utilities.

Sort the list by CPU use. Also check memory and disk activity, since those can make your computer sluggish even when CPU use is low.

If the browser is the main user, inspect its open tabs and extensions. Some browsers have a built-in task manager that shows which tab or extension is busy. Do not end unfamiliar system processes at random; look up their names first.

Updates, video calls, games, antivirus scans, and cloud backups can all cause similar symptoms.

When to suspect hidden mining or a scam

Unauthorized mining is often called cryptojacking: someone uses your device’s resources to mine without your consent.

Warning signs include heavy activity while you are doing nothing, mining that starts again without permission, or a recently installed extension using unusually large amounts of CPU. These are clues, not a diagnosis.

If activity remains unexplained:

• Remove extensions or apps you do not recognize or trust.
• Update your browser and operating system.
• Run a full scan with your operating system’s security software or a trusted security tool.
• Avoid “fan fix,” “mining booster,” or “instant cleaner” downloads promoted by pop-ups.

Do not disable antivirus protection because a mining site tells you to. Never give anyone your wallet’s recovery words—the secret words that control access to your funds—to “repair” your computer.

Do not overlook cooling

Use your laptop on a hard, flat surface, not bedding. Keep vents clear and follow the manufacturer’s cleaning instructions.

If fans stay loud even with little CPU activity, dust, a failing fan, or another cooling fault may need attention. Stop demanding tasks and seek repair advice if you notice repeated shutdowns, grinding noises, or excessive heat. Shut down and unplug the device if you smell burning.

The bottom line

Pause mining first and check whether the noise and slowdown settle. If they do not, investigate resource use and cooling rather than assuming mining is the only cause. You should never have to accept an unusable computer—or weaken its security—to keep mining.