That surprised me as well, for the first week or so of having it I had to have the fan onboard cranked to 95% and another fan pointed at it point blank or it would overheat even on minimum settings.
Discussion
could be a range of things from software to the chip itself. Most bitaxes run off dismantled or not fully functioning ASICS, and they sell the individual chips and well, yeah some are just duds vs others they pull off. It's really a great toy for "make your own miner" - I'd love to make my own sometime