Naah, they're about the same efficiency as Cu spreaders, just a fraction of the weight, and with a few nifty features seen in no other material that I know of.The main reason for me to use pyro-carbon heatspreaders is that it besides having high conductivity, is directional. This allows me to make all the critters run under the same temperature, even during the power up/heat up sequence. Had I needed to use copper for the Donuts for instance, I would have ended up with like 20-25kg higher total weight. I honestly think that they are heavy enough as is.Magura