Yes I noticed as well that it’s extremely efficient. Last evening I replaced the fan+heatsink with a larger heatsink attached using thermal tape, a solution that I used with success on the much hotter RK3288. I’ve ran stress-ng for 20 minutes, the SoC temperature reached 76°C stable after 10-12 minutes, for about 53 on the heat sink, which is very reasonable:
At least that shows some good stability on the power path and the temperature.
Also Ifound a bit of info on this PVTM thing that gives me a varying top frequency at boot, it’s a concept I never heard of which tries to estimate the “quality” of the silicon based on a free-running clock, the temperature and the voltage, to estimate the max frequency that will be supported. Mine has a random frequency at boot because the measure oscillates between 1742 and 1744, the latter being the next offset 
I find the concept interesting, except that it should then not remove the OPP from the list but just condition them by voltage/temp as well. I.e. if you manage to cool your board or to slightly overvolt it (or both), no reason to deal with the constraint. Anyway I think that just fiddling with the DTB to adjust the threshold will do the job, so for now I don’t really care. And possibly that we’ll be able to enable them when boost will be enabled, that’s something to check as well.
Last point (I’m grouping all my comments due to the limit of 3/day), I tried to run a network test at 2.5GbE but it ended up being at 1G because the other NIC was an intel X540AT2, and that one only supports 1 or 10G but not 2.5… I ordered a 1/2.5/5/10G one to run more tests. However during this time frame I could notice that queues were totally uneven on Rx (a single CPU was used), so there’s possibly room for improvement using ethtool. Something else to keep on the check list!