Good heatsinks but quality control could be better, some fins were bent about halfway and I had to straighten them. I used a special thermal epoxy compound to glue them to my Rpi 4b chips (CPU and memory) and they work better than expected. My R-Pi 4b overclocked to 2200MHz at overvoltage=6 never went above 53.6*C. I also installed the smaller 6.5mm heatsinks that this brand offers on the Power Delivery chip , and that made it more stable. If you do this with yours, remember to conformally coat