There was a NYTimes profile at the time of Kent's efforts, and they IIRC literally got the UC Santa Cruz administration to hand over desktop computers destined

There was a NYTimes profile at the time of Kent's efforts, and they IIRC literally got the UC Santa Cruz administration to hand over desktop computers destined to go to various people for a few months to assemble into a cluster. So it was likely a bunch of pentium pros or similar. Not a Beowulf cluster, of course, but whatever clustering software Kent had hand rolled out of C for the purpose.