UNIX performance on a VAX & 68020

[Polderman Paul]

Benchmarks show that a 68020 is at least as fast as a VAX-11.
But if I start e.g. 6 C-compilers on a UNIX-system running on a 68020,
the performance collapses completely (even when no swapping is necessary),
where on a VAX the system-performance stays reasonable.
I wonder why this is so, when the CPU-speeds are roughly the same.

I asked several people, but none of them seems to be able
to give me a clear answer.

--
Paul Polderman (polder at cs.vu.nl)