The RK3399 Overclock/Undervolt/Voltages Thread

[generaleramon]

Unfortunately, I cannot help you with some hard facts, but I'd like to know about the temperatures of the undervolted SoC, under full load?  Are there any significant differences compared with the standard voltages?

well i don't have exact numbers for that, but from my limited experience overclocking/undervolting the PBP i can say that if you want to lower the temps than you have to improve the contact between the SoC and back cover. I noticed the thermal throttling at 70degrees when compiling the kernel (2-3 hours), pressing down the back cover in the soc area was instantly lowering the temp by some degrees, so i took another thermal pad and put it on top of the original one. That helped, the back cover now gets hotter and faster. BUT, as i want to overclock and stress test the 2 clusters with Linpack-HPL2.3(which is very heavy) i needed more thermal mass, so i used thermal glue to glue a 2-3mm thick metal plate (50x50mm) on the backcover, soc area. This was i can use a thin thermal pad and i have way more thermal mass. Using small fan barely running at 5v i can stresstest the 2 cluster at max clock(1.7Ghz/2.1Ghz) keeping the SoC under 75degrees(the standard limit is 70 but i increased it to 80 for now just for testing). Firefox with GPU rendering enabled use barely 4W when watching a 720p60 video on youtube, temps are under 40deg. Under a normal daily use i never see the SoC go over 50degrees
so in the end i would say that considering the thermal mass, the soc is going to throttle no matter what, but undervolting it you can make it run for longer. In my case, if i keep stock clocks and decide to just ondervolt i can lower the A53cores by 150mv and the A72 by 50mv @max clocks. Not bad.