Sorry, but alternate CPU designs were never outperforming x86 by an "order of magnitude", especially not at a lower clock speed. That is a complete exaggeration. I was around during that time period and can find nothing that supports this. The Alpha was fast, yes, but you're talking 2 to 3x best case with floating point compared to a 2 to 3x cheaper Intel system. I did find some old benchmarks: http://macspeedzone.com/archive/4.0/WinvsMacSPECint.html

UltraSPARC was not very competitive. Those machines were very, very expensive and you didn't get much bang for the buck. They weren't even that fast. The later chips had tons of threads but single threaded performance was pretty bad...