It's a clear trend: computers are getting smaller and, fortunately, lower in energy cost. For those who want to assemble a small PC themselves, there is the world of Mini-ITX. These motherboards are only 7x7 inches and very low on energy cost. And as it seems, in some cases you don't even have to give up on speed and possibilities...
At the end of the 90's, processor- and chipset-fabricator VIA took over two small processor fabricators: Cyrix, and IDT Centaur. At the beginning of 2001 VIA introduced, based on IDT-technology, the VIA C3 processor. Even though VIA was not big at all in the processor-market, that single processor had one big advantage. At that time, VIA was the only one that had a low-energy cost at the top of their agenda, and as a result the C3 was using way less power than the Pentiums and Athlons that were all over the market. And because the processors weren't even getting close to the competition on processor performance, VIA decided to focus entirely on the niche market of small, low-energy PC's. The at that time existing standard motherboard sizes, ATX and Micro-ATX, were not suitable to assemble very small computers. A Micro-ATX board measured 9.5x9.5 inches and so the housing is relatively big too. To widen the market of small computers, VIA introduced in March 2001 at the same time as the VIA C3 processor, the ITX formfactor. ITX boards looked much like ATX, but were only 8.4x7.5 inches, and with that, a bit smaller already.
There was no talk of a real success: in the market of normal computers, the ITX was barely noticed and VIA was making its few good deals at the industrial market. A major reproach towards ITX was that motherboards were indeed smaller, but the difference with Micro-ATX was that small, that fabricators of housings and motherboards saw too little market to consider getting seriously involved with ITX. For that reason, VIA introduced in 2002 an even smaller variant to the market: Mini-ITX.
Measuring 17x17 centimeter a Mini-ITX board (right) is a lot smaller than a Micro-ATX board (left).