Overheating issues on Orange Pi 4B

Hey folks,

So here's the setup I have:

• I have an Orange Pi 4B running the Orange Pi 4 image and kernel 5.6.17-rockchip64.
• I have an Orange Pi 4 running the Orange Pi RK3399 image and kernel 5.4.26-rockchip64 (cause when I got it, the Orange Pi 4 images weren't out yet).

The OPi4 is running just fine.  I imagine that I'm running the wrong DTB and that not all the hardware is working properly -- but the hardware I need is working just fine.

The OPi4B is another story.  It'll boot just fine, and it'll run just fine for days/weeks on end -- as long as I don't put it under any sort of heavy CPU load.  But if I start running anything CPU-intensive (such as compiling software), it'll run for a few minutes before rebooting.  I suspect that the CPU is overheating and the thermal protection code is tripping -- cause if I run htop while the compile job is going, I can see the CPU temperature rise until it hits 94°C, after which it reboots.  It kinda looks like not all of the cores are throttling down -- at the point that it rebooted, the big cores were running at 408MHz, but the LITTLE cores were still running at 1.51GHz.

I'm not sure what to do here.  I've done a side-by-side comparison of the DTS's for the two, and I can't see any meaningful differences between the two -- but then again, I'm not familiar with DTS's enough to really know what I'm looking at.  I've also tried several different kernel versions with no luck.  Can anyone give me any pointers?