The problem is still heat-related. The question then becomes: where’s that heat coming from?
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The CPU and fan
It sounds like you know this already, but let’s review. As you work on your computer, your CPU generates heat. There’s a fan inside your machine that keeps it cool. When the fan is clear and the inside of your machine is clean, then the cool air has a chance to flow through and keep the CPU temperature under control.
The most common problem with a computer fan is that dust accumulates inside your machine and prevents the fan from blowing cool air through the computer. If that’s blocked, then the heat that’s generated by the CPU just accumulates and never cools down enough for the fan to turn off.
Another reason why your fan might be coming on could be that the CPU is being heavily used. Like I said, the CPU generates heat as you work. It generates more heat the harder it works.
When the heat is on
So how or why could the CPU be generating heat now? For some reason, it’s working harder than it has in the past.
That could be normal use. If you’re running something that’s very CPU intensive, like video decoding or encoding software, for a long time, I would expect the fan to kick in because the CPU generates heat from all of that work. It might be unexpected, but it’s still normal use.
On my MacBook Pro, I often run Parallels so I can run a Windows virtual machine. As it turns out, that’s just enough extra processing that even though I’m doing nothing, the fan on the MacBook will kick in every once in a while.
It surprised me. If I turned off Parallels, then the fan never kicked in. It’s normal in the sense that it’s the result of something that I was running intentionally, but it was unexpected.
The CPU, the fan, and malware
The other reason why the fan is running could be related to malware.
Depending on what it wants to do, malware can cause your computer to start working in ways that make the CPU work harder.
The solution is to get rid of the malware. If this is the case, make sure:
- Your anti-malware software is running up to date.
- Your firewall is in place.
- You’re doing all of the right things to keep your computer safe on the internet.
Of these scenarios, I don’t really know which one is happening to you. Check out my article, “Who’s hogging my CPU?” which will actually show you how to use a tool called Processor Explorer (that you can download for free from Microsoft and run). It will show you which processes and programs on your computer are actually using the CPU.
If you find that the CPU is spending most of its time idle, then it’s not the CPU heating up. It’s something else. You may find that there’s a process or a program that’s using more CPU than you expected and from there, you can make some decisions.
I will throw out one last comment. Ambient temperatures, or the temperature in the room, can contribute to this.
Normally, we’re talking about the temperature in a room being in the upper 60s Fahrenheit with CPU temperatures well into the 100s. If the room is 10 or 20 degrees warmer because you’re in the middle of the heat wave, then it’s possible that the entire computer could be just warm enough to push it beyond that threshold where it says, “You know, I should really turn on the fan.”
Those are the ideas that come to mind. Still, you took care of one dust issue. Next is to look at what’s using your CPU now.