@jgalt91 I think most of humanity is unoptimised and wasteful; so many people drive 4-occupancy vehicles with only 1-occupant to work everyday.
That said, I have some good news!
@RRZC777’s passive radiator reached thermal equilibrium after 30 minutes of running the Antutu 8 CPU stress test on Android on a VIM3L. Equilibrium was reached around 51C, at an ambient temperature of 26C.
I’ll move on to testing the VIM3, still on Android since that’s the easiest OS to run a standardised test on. I will end-off with the Edge-V, and some tests involving Ubuntu. I also noticed that the maximum temperature reached differs between using the 10W adapter (lower) and the 24W adapter (higher), so all my tests will be done with the 24W adapter.
You may also be wondering what those 2 little dips are in the temperature graph…well Antutu’s stress test only lasts 15 minutes, so I had to restart the test twice to reach 45 minutes.
VIM3, Android, Antutu 8, 45 minute stress test, 24W adapter, @RRZC777’s passive heatsink . The large dip earlier was me falling asleep, and not noticing that the test had finished. Nevertheless, we can see the curve slowly reach a plateau around 70C, at an ambient temperature of 25.5C.
I was planning to build a cluster of 5 VIM3 to test but I do have some concerns on the cooling. (Tropical country / Vietnam)
You have some recommendation to tackle this for cluster?
May be do a grape and 1 large fan, etc…
@karibu I’ve added a 35x35mm heatsink with a thermal pad to my Edge-V heatsink where the fan should sit, which fits perfectly. You can find them for 1-2 bucks each one in internet. With that, adding a low power fan pointing to your VIMs should be enough. Or an alternative is putting them in a box/tube with 2 sides open: one connected to an extractor that sucks the hot air out, and the other side where the cold air comes in.
With the “stock” Khadas 3705 Cooling Fan and New VIM Heatsink, the equilibrium temperature is around 51C, at 25C ambient, on the VIM3. This is again running the SoC at maximum load using the Antutu 8 stress test. Notice that due to the New VIM Heatsink’s small thermal mass, it reached equilibrium a lot faster than @RRZC777’s large passive heatsink.
This test only took 30 minutes, and the 3705 cooling fan was set to “automatic speed mode” from within Android. The sharp dips at the start of the test was myself placing my cold fingers onto the heatsink, notice that since my body temperature is around 37C, my fingers sucked heat out. The second sharp dip is myself restarting the test around the 15 minute mark.
30-minute Antutu 8 stress test on the Edge-V (RK3399), using @RRZC777’s large passive heatsink. I stopped the test at 30 minutes, as the SoC was experiencing significant thermal throttling, and since our aim is to avoid that, I saw no need to proceed further.
Ambient temperature was at 30C, and the likely equilibrium temperature would be 75-80C. This is already too hot for most people’s standards.
You’re welcome! Now my issue is: should I rerun the tests using CPU Throttling Test…or move on to Ubuntu? Ah choices choices. Temperature is higher today too, 28C (with the air conditioner, 30C is a little too high for my liking, my brain is starting to throttle)
Just to properly end-off this round of testing with Antutu 8, here’s the final result for Edge-V with active cooling (3705 fan + new vim heatsink), and using the 24W adapter. The fan was again running at “automatic speed mode”, and I note that it definitely sounds louder as compared to when it was stuck onto the VIM3.
This is what I made with the 35x35mm generic heatsink with a thermal pad under. The idea for a totally passive top heatsink would be this, but as a whole block of 70x35mm, 15mm tall instead of the 5mm height that the actual heatsink has (my addition is 10mm height). The problem I see with the bottom heatsink is not that it’s in bottom per se (although its a problem since hot air goes top) but the thickness of the thermal pad to avoid touching bottom connections with the metal plate. Metal has much more thermal conductivity than thermal pads, and the thicker it is the more it insulates, it should be only a layer to fill the gaps between metals alas thermal paste.
Or just the metal plate without the left heatsink part so we can add the heatsink we want that fits our user case?