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Comment by martinced | Hacker News Reader

I'm a bit surprised by the most voted answer by a user who has 80K rep on SO.

By this part:

"If you decide to compile and run this, pay attention to your CPU temperatures!!! Make sure you don't overheat it. And make sure CPU-throttling doesn't affect your results!"

Fair enough for the CPU throttling.

But did the nineties just call? Computers dying due to CPU overheating was all scary and spooky back when we were running old AMDs and old Pentium CPUs but I haven't own any CPU that could die due to overheating since a very, very long time. They do automagically throttle to: a) make sure they stay within their TDP specs b) make sure they don't melt.

I mean: honestly, scientists should start to worry about overheating their CPU that are going to melt?

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haven't own any CPU that could die due to overheating since a very, very long time

You probably have, CPUs are just smarter about it now, and throttle themselves back:

http://www.intel.com/content/www/us/en/architecture-and-tech...

If you have a densely packed blade farm, you could easily exceed the cooling capacity within the rack. Another scenario is laptops.

Senario: this code triggered a shutdown on my computer due to poor ventilation. If I had programs open I would have lost my documents.

I think the only thing in favor of the argument that it might overheat the CPU is that many more functional units on the CPU will be active at once and with no time in between. Normally they would be idle due to cache misses and memory access.

I don't think with modern CPUs that this is a problem, but you would have to test to find out!

I'm guessing since you're disabling throttling to get better results you are also disabling the safeguards that prevent such failures from happening.

Outside of leakage current CMOS/MOSFET circuitry draws current during state transitions. So, yes, more bits flipping per unit of time will cause additional heating, sometimes dramatically so. This is the reason the last generation of iPads get so hot: Four tomes the pixels means that you have the potential to have four times more bits flipping in the display processing pipeline, hence more heat. Try running footage where every pixel is changing on every frame and see what happens.

>I mean: honestly, scientists should start to worry about overheating their CPU that are going to melt?

My officemate is working with some neural networks researchers, trying to get near-peak throughput running convolutional neural networks on NVIDIA's new K20 GPUs. Several GPUs have already died and they're looking for better cooling for the rest. So, I don't know if peak utilization of multi-core CPUs can still be hazardous, but it's definitely true for graphics cards.

I'm a bit surprised by your smug attitude.

So being correct, raising an interesting issue and discarding urban myths is smug now?

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