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 Darrell Beecher

They work fine when used as intended, slight temp drop but nothing crazy. I use them a little differently than I should. They are used in combination with a Nespi case + For the chip on the bottom (RAM I think) I installed two small black heatsinks with their original thermal pads. For the processor, I removed the thermal pad and added a small amount of mx-4 thermal pad. insert in the hope that it actually lowers the CPU temperature. And yes, it works much better. I did the same with the small chip. The last thing I did was add a fan to the Nespi case. Overclocking the processor from 1.2GHz to 1.4GHz and overclocking the GPU by 50MHz. remains below 60 °C. I'll probably try to climb even higher.