RiSE mP6 - MP6430CNE ES / M1A USA / 1998 Rise Technology
This engineering sample of the Rise mP6 isn't PR-marked, but seems to be a 166 MHz CPU as you can see hand-written. This Rise CPU comes on a CPGA packaging instead of all the other ones. Revision is MP6430 while the other (more recent) ones are MP6440. I'll try to check soon about his CPUID.