Is the heat in these compact designs really a problem?
its only a problem if you try running it open-air. they are designed to be encased in a chassis with high-powered fans for intake and exhaust (see octominer case with 7 delta fans). In this configuration I have 8 cards crammed together and the rigs are in a hot garage in Texas and the gpus are plenty cool due to the massive airflow
Yea, as with the server PSUs, compact designs depending on fans going ooooiiiiiiii...
So MoBo designed for for airflow sensitive GPU packing, but with a size that does not fit inside 19" cases...