I've only seen one multi processor Pentium system, and that was a DataGeneral Aviion. It was also NUMA instead of SMP, so that made it rather interesting.

I have seen plenty of multi processor Pentium Pro and later systems. Which really makes since as it was not until the PPro that Intel started getting serious about the high end market. Back in the day I used to have a Dual Pentum Pro 180MHz system. It was the bomb. It was so cool having and SMP system.

I have heard of multiprocessor 486 systems, but have never seen one.