Scyld performance problems

[Tom A Krewson]

I am having a performance problem with my Scyld Beowulf. I have been
testing with 5 machines on a 100-megabit switch while using the Linpack
benchmark. With 6 machines (1GHZ server, 5-333 MHZ clients) the results of
the linpack benchmark is .1 Gflops. With just one machine (1GHZ server) I
get a .5 Gflops (4.670e-01) result. I tried using 9 computers and the
performance is even less at .09 Gflops. I have tried 3 different switches,
and the cheapest (I assume a cut through switch) gives the best
performance. 

I have downloaded a parallelized pi calculation program the reverse true -
the more computers in the cluster, the faster the calculation.  

Am I reading the results incorrectly? What might cause this poor
performance?