I finally got around to this, and swapped my Intel i7-1165G7 board back in to retest. The board with PTM7950 has been in use from ~July 2022 to early November 2023, so well over a year. Initially, I thought I had cleaned out all the dust (there was a lot), ran all the tests in my original post again, and was seeing over ~5C hotter temps (10C at the extreme, at high power). I was puzzled, and thought my PTM7950 application had degraded. Then, I rechecked by partially taking off the fan cover, and lo and behold there was more dust. I cleaned that off, reran the tests, and temps were back to how they were originally!
The area in the green boxes [a] are easy to see and clean dust from. However, the area in the red box [b] is hard to get to and clean:
And I did not want to remove the entire heatsink for the risk of damaging my precious PTM7950 application. So to avoid that, I took out the entire mainboard, unscrewed these 2 screws (yellow boxes [s]) on the front side:
as well as these 3 screws (yellow boxes [s]) on the back side. Afterwards, the area in the blue box [bmc] is still attached to the heatsink via a bent metal clasp? which didn’t look like it could be easily undone without breaking:
I kept the rest of the heatsink assembly screwed in/attached to the mainboard.
Finally, with all those screws undone, the fan can be gently pushed out enough so that the bottom of that hard to reach area (red box [b]) is revealed:
If you zoom in, you can see that there’s dust blocking the fins and yes, it doesn’t look like much. But little amount was causing an increase of 5-10C! I had already removed a ton of dust from the green boxes, so my temps must’ve been even much higher. I definitely noticed an increase in fan load/noise during regular usage (but let it be), and am confident it was the dust. Now I wonder if the increased fan load led to a decrease in battery life because:
After I cleaned that area (very easy to do with a cotton swab and some alcohol, or carefully with water) and reassembled, temps dropped back to how they originally were on day 1 PMT7950. Yay!