Latest build causes extreme CPU/fan-spin

Something not working in GZDoom that's not a bug? Is the display a bit quirky and unexpected? Post here.

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dpJudas
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Re: Latest build causes extreme CPU/fan-spin

Post by dpJudas » Sat Nov 26, 2016 12:17

The fan speed is way lower because the CPU and GPU temperatures are lower. They usually don't go on max until the temp gets past some threshold (let's say 80 C) where it goes "oh shit, if we don't start those fans at max now the computer is going to overheat".

I don't know why it changes from day to day, but it could be many things. Are you playing from the same physical location each time? The surface below the laptop and the sides of it where the exhausts are located influences it a lot. Same with room temperature, and possibly other software running on the laptop. All I can say is that you might be able to reduce the chance of it happening by reducing the graphical details a bit. Either way, I don't think it is a bug in GZDoom causing it.

Ace83
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Re: Latest build causes extreme CPU/fan-spin

Post by Ace83 » Sat Nov 26, 2016 15:53

But if you compare the two images, you'll see that the CPU and GPU temperature is almost the same. But with the huge difference between the fanspeed, 6000 rpm as opposed to 1000 rpm. I think that's the weird stuff here.

Circumstances are the same, laying in bed with the laptop on a simple laptop stand. The only difference I can think of was that I had a few hours Logic Pro session prior to GZ Doom, but the computer was idle a couple of hours in between.

Thanks for the suggestion, but I'm not convinced the graphic settings in GZ Doom is what causing this. That's because I had the same settings both yesterday and today. Yet, if this was relevant somehow one would imagine the fanspeed being constant at some states in between sometimes, for instance 2000 rpm or 3000 rpm. But this never happens, lol.

Probably not a GZ Doom bug, but this is the only program when this happens. I'll try to remember to come back to this thread in case it happens with another program so we can completely rule that out. Either way, it seems to work again now.

And clockwise btw, feel free to continue brainstorming / report any relevant info.

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Re: Latest build causes extreme CPU/fan-spin

Post by _mental_ » Sat Nov 26, 2016 16:57

It's not correct to compare GZDoom with other programs. You need to find a game with similar CPU and GPU load to do so.
Programs usually cause spikes of loads interleaved with idling. This is not the case with games where CPU/GPU consumption is more or less stable.
Let's say if you will apply complex filters in Photoshop pretty often then you will get the same fan speed after some time.

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Re: Latest build causes extreme CPU/fan-spin

Post by dpJudas » Sat Nov 26, 2016 18:22

Ace83 wrote:But if you compare the two images, you'll see that the CPU and GPU temperature is almost the same. But with the huge difference between the fanspeed, 6000 rpm as opposed to 1000 rpm. I think that's the weird stuff here.
They are not remotely the same. There's 10-15 C difference between them. First picture has 71 C, second has 85 to 90 C.

The fan speed itself is most likely coded by having only a few steps: off, 10%, 25%, 100%. Once it passes 80 C it switches from 25% to 100%. Why such an aggressive slope? Because users hate noise and most lightweight stuff can get away with the three first modes. Why not more steps after 25%? Because Apple saves 1 cent per laptop, and after selling a billion of them the CEO can go play golf with that money. ;)

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Re: Latest build causes extreme CPU/fan-spin

Post by Ace83 » Fri Dec 02, 2016 3:56

Thanks for further brainstorming, and after some more sessions I'm willing to buy the threshold theory... For now. :P
Either way, only at bigger maps and lots of enemies this happens now so I'm fairly OK with it.

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Re: Latest build causes extreme CPU/fan-spin

Post by Gez » Thu Dec 08, 2016 17:25

If there is anything that obstructs the airflow out of the laptop (a pillow for example) then the fans will start to go faster because the heat won't dissipate fast enough. The temperature inside the case isn't uniform, and the same CPU temperature can be not much of a problem if the rest of the case is still quite cold but more worrying if the rest of the case is heating up.

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