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Maybe I should write more about temperature on one place.
There are a lot of different factors which have impact on temperature. In no particular order and not complete:
- Ambient temperature
- SoC characteristics
- PCB design
- voltage & frequency settings
- enclosure
- cooler
- software
Ambient temperature is easy - in summer, you will read out higher SoC temperature than in winter (let's put aside air conditioning)
Surely you have no influence in next two, except when you are deciding what to buy. Lets make HW comparison between OPi One and OPi Plus 2E. One has small PCB means smaller radiator, which means less heat dissipated. Plus 2E has much larger PCB which means that board acts as a pretty good cooler. Of course, PCB designer could screw up things here, but IMO Xunlong has done pretty good job. I also heard that integrated ethernet in SoC is not good for thermal characteristics (not sure how much influence this really has). One uses integrated ethernet phy, whereas Plus 2E has external ehternet phy.
Next, core voltage & frequency settings. You have to do a lot of testing to find (near) optimal settings. Fortunatelly, tkaiser from Armbian forum did a lot of tests here. But still, if you have One, you have only two core voltage settings, while Plus 2E has possibility to set voltages in steps of few mV, so you don't need to overvoltage cores when there is no demand. Fortunatelly, OE is capable of using HW decoding, so most of the time, CPU doesn't do much. I tested 4K H265 video and cores were at lowest setting (480 MHz) all the time. MPEG4 video needed a bit higher clocks in the average, but it was still at the lowest setting some time. This means that Plus 2E profits again here.
Enclosures and coolers... Well, if you don't have much experiences, you can quickly make a mistake with enclosure. Vent holes must be the right size and in the right places. I don't have enough experience here, so I don't use them. Coolers are good to have, but again, you must be careful how you attach them. Too thick thermal paste or air bubles and you are actually in a worse position.
And last, but not least - software. Software surely represents some workload. So you can make board cooler just by closing some demanding programs. But the system is not useful much if you don't have any program running. OE is often compared to Armbian in regards of temperature. I'm trying to use same tricks for lowering temperature as Armbian, but use case is completely different. So if you are doing a comparison, at least try to make same workload. In this case, run Kodi on both systems (home screen is enough) and only then compare temperature. There are also some software settings, which influence might end temperature. Disabling RSS feeds definetly brings lower temperature in a home screen.
Oh, and SoC highest junction temperature is 125°C, which means you are ok with some safety margin till around 100°C. But of course, in general, lower temperature means longer lifetime. 70°C is certainly not optimal, but manageable.
P.S.: If you find some reasonable change which would help lowering temperatures, please tell me. I found out that I must sync at least cooler table with Armbian. |
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