Review on Easycargo Raspberry Pi 4 Heatsink Kit (Pack of 20) - Aluminum & Copper with 3M 8810 Thermal Conductive Adhesive Tape for Enhanced Cooling of Raspberry Pi 4 B & Raspberry Pi 3 B+ by Danny Zapata

I noticed that there is a chip on the bottom of my Raspberry Pi 3B+ that gets very hot and I suspected the Pi was slowing down due to excessive heat. I didn't think I had enough room under the board for a finned heatsink (although I probably did), so I used a flat copper heat spreader. It worked - the hotspot is much more spread out and runs much cooler (tested with a digital thermometer). I also used a finned heatsink on the main processor. There are no more signs of overheating-related throttling.