Just a little fun post inbetween. Ingo Korb of sd2iec fame (that’s the project that got me started on sd2snes in the first place!) had the chance to take thermal images of a running SNES+sd2snes. Some people, including myself, found that the sd2snes gets quite hot in the SNES. However the heat actually comes from outside the sd2snes, that is from inside the cart slot! The SNES’s linear voltage regulator produces a lot of heat that gets radiated into the cartridge slot (among other places).
These images illustrate it quite nicely. There are little hotspots where the chip dice are but most of the heat comes from below / behind.