How hot is too hot?

I'm running a desktop in a dusty environment. It's a pain to open it up and blow the dust out out of the innards, so I'd like to be able to see when it is heating up and it's necessary to clean it.

So I got Speccy, and it tells me that that the average CPU temperature is 40 degrees C at most. This doesn't seem awfully hot to me, but can anyone tell me when to start worrying?

The scale of the speccy display ... I will guess that the scale is adjusted to whatever the current temperature is, and so I should _not_ take it that the top of the scale is the danger point. Is this correct?

Some mentioned a "flame" icon. What's this?

My machine is an Intel Core i3-2120 CPU @ 3.30GHz. I just looked at the Intel site; there is a "Tcase" of 69 degrees. So I guess that if the temp starts to get up to 50, it's time to clean.

Any comments?

Thanks

Welcome to the forum,

I've recently built a new rig with a Core i3 7th gen running at 3.9GHz and it pretty constantly sits at 270C, as shown in the BIOS and by Speccy.

So already I'm thinking 400C is nowhere need a range to be worried about, but high none the less.

Perhaps simply increasing airflow or getting a better/newer CPU heatsink and fan would help.

As to top temp range, I'd get concerned if it was hitting 600C and above.

You'd think if it's getting too hot that the CPU would start throttling performance which should be noticeable.