If you would read you would know, that it is probably a problem with the PSU (cooling) not the Avalon modules
An "Avalon unit" includes every component in the box with fans. The contents of that box are irrelevant. If they say it uses 450W, and it uses 620W, then they are fucking liars. Plain and simple. "It's the power supply" is no more relevant than "it's the ASICs". The simple fact is that the shipped unit does not work as described.
If the chips themselves use 450W, then that is of academic interest only, since the "Avalon unit" sucks far more than that from the wall.