Far from important, but pentium cpus didnt have mmx originally. It wasnt until halfway (or more) through thier lifecycle that MMX was added (P166MMX was the 1st iirc, but later on it was added to versions as low as 133mhz). At the time it was a pretty big deal, may be antiquated now (although revised versions are still in use today, so it must be worthwhile), but computer hardware evolution doesnt happen overnight, these are all important steps that led us to where we are today.
I had the 166MMX and I over-clocked that chip by over-clocking the bus. It was mad fast running that way and very stable...
