Thank you very much!
I didn't have a thermal camera, but based on touch, I can vouch for the hotspots. I also learned that the rectangular chip next to the big hot square one is best left alone. I tried to put a heatsink on it and it caused the Pi to malfunction. Closer inspection shows me that there are two small components right next to it that are slightly taller than the top of the chip and apparently get shorted out. Fortunately that particular chip doesn't get very hot.
Incidentally, I'm using one as a video recorder/media manager with only passive fin heatsinks (no fan) and it['s extremely reliable in open air. In theory, video transcoding should be giving it a good workout, although I haven't measured.
Some practical notes. The claim has been made that a Pi 4 can completely replace your desktop. In truth, I've not had significant issues using even a Pi 3 for "office tasks" and running CNC control, but on the Pi 4, I went whole hog.
On a 1GB Pi 4, I concurrently ran a web browser, the Arduino
IDE (which is a
Java app), and Emacs - the operating system that pretends it's a text editor.
You don't want to do that, actually. I didn't see CPU performance issues, but Java eats a lot of memory and web browsers are notorious pigs. A single Gigabyte of RAM can't accomodate all that and virtual memory started thrashing. So hard, in fact, that sometimes it was faster to reboot than to wait for the storm to subside.
I expect that my 4GB Pi 4 probably won't have this issue, although until I finish a current project I won't be able to confirm that. Once the 1GB
unit is freed up, I can simply swap SD
cards, which is very convenient.
I hope they don't discontinue the Pi 3, though. It may not scream like the Pi 4, but it's much more energy efficient and more than adequate to run my audio apps and stuff like that.