And finally, after unmounting the extension boards and the cooler, you can see the motherboard: ASUS P4SQ on SiS651+SiS962L. Surely, the chipset is not up-to-date, so why was it chosen? It is all about the restrictions on the CPU. The external PSU supplied with DiGiMatrix only gives 120 W, so modern Pentium 4 CPUs (to say nothing of the Prescott-based ones) can't be used. Power, in turn, is obviously limited by the cooling system: you can't keep an appropriate temperature of a hot top CPU in a compact case without raising significantly the noise level. Many companies use more powerful (and louder) coolers in such a case, ASUS did it the other way round. But the solution seems sensible considering the absence of a videoaccelerator and the fact that powerful CPUs on home PCs are mostly needed for playing games.

Initially, the specs mentioned 2.4 GHz as the maximal frequency (because Pentium 4 and Celeron, based on the same core have the same heat-emission, we won't hereinafter specify which of the CPUs is meant). However, the latest BIOS version raised the limit to 2.66 GHz. Before that, only ancient Willamettes up to 1.6 GHz (and surely, all the Northwoods up to the mentioned frequency) could be fit for the device. Now DiGiMatrix can be supplied with all Celeron models up to 2.6 GHz and Willamettes up to 1.8 GHz. It will be recalled that Prescott-based CPUs can't be used in this mini-PC.