jcyr wrote: ↑
Tue Sep 10, 2019 10:08 pm
procount wrote: ↑
Thu Jun 27, 2019 10:27 am
A fan always wins in my view.
Basic thermodynamics agrees with you. Given a big enough heat sink and a low enough ambient temperature you will never heat soak it, However you do have issues with boundary layers. You also have the issue with local ambient, if your case does not have enough ventilation. Turning the Pi on its edge with the heatsink fins in the correct orientation, lets convection currents help. Cheap heatsinks with crappy attachment pads may actually make things worse as the tape acts like an insulator.
However, active cooling will always be more effective and not require low ambient temps. Yes there is a potential noise issue (solvable with good, larger fans turning at lower speeds) and a power issue (solvable with a decent power supply). It totally depends on your use case but for desktop usage with lots of browser action a fan is a simple, easy, cheap solution that just works for me, since I want to Pi to live in a case. If you can live with it naked, and ambient temps are not too high, mounting it vertically may work. @Jamesh reports good results running that way and I suspect he logs lots of hours with a Pi.
The other issue to consider is what temps are you trying to achieve. As long as it is not underclocking, life is good. Most computers have their chips buried inside (especially laptops) and users are not aware of how hot things get. With the Pi it is much easier to become aware of this and then worry unnecessarily about it. I have a number of laptops that are not really useable in my lap due to this. Even my Chromebook gets uncomfortably hot right where the cpu is located if I am watching videos for extended periods. Yet it functions just fine with no fans, in a much worse thermal environment.
And so we are right back to the conclusion of all the threads so far. Fans work better. Heatsinks, done right are good. Pi 4 can run without either depending on your use case.