I bought these and a fan to put on the back of the RTX 3090 to keep it cool. The backplane is mounted on a RAM that has been cooked at 105C. As soon as I glued them on, they got unbearably hot, so the glue transfers heat well. Attaching a fan made them feel cool, so the fins provide a good surface for air to dissipate heat. Downgraded my RAM by 10C.