The X704 was the first, and only, processor produced by the Exponential Technology company. Although many engineering samples were produced, their funding ran out before large-scale fabrication could begin.
The X704 we designed based on a concept called BiCMOS, a marriage of CMOS and Bipolar logic, a system that was supposed to achieve much high clock speeds than the CMOS logic used at the time (and still used in many processors today). Intel had used Bipolar Logic in the original 60- and 66-mhz Pentium processors, though they were using a 'half-assed' implementation at generated huge amounts of heat and required large dies. The X704 also used a Flip-Chip design, seen in Socket 370 Pentium !!! Processors. BiCMOS was supposed to take the best of both worlds -- Bipolar logic for speed, and CMOS for costs and heat reasons.
It was supposed to start at 533mHz which, in 1996 was insanely fast -- the fastest PowerPC processor at the time was the 240mhz 603e and the fastest Intel chip was the 233mhz Pentium MMX.
Unfortunately, when Apple pulled the plug, no one was interested in funding them, and so they went Chapter 11 and folded, and the technology was later bought by Motorola.
The most important thing about the X704 was, however, the fact that various engineering samples were differently coloured, from Indigo to Lemon and the most common, Magenta. It was the iMac revolution before the iMac happened.