What? P55 only has one chip called the PCH. It doesn't have two chips like in previous generations- the northbridge and southbridge (called ICH and IOH on X58). So many manufacturers put a heatsink where the NB used to be just to look cool but it serves absolutely no purpose, just like on the UD5. Here is an example: the Biostar Tpower i55.
they should save the money on gimmicks like this to add 1 or 2 pcb layers.