I have a Tyan Tomcat I board, which is a single-processor
Pentium board but a close cousin of the dual Tomcat II.
Apparently too close.

At boot, the kernel says :
total of 2 processors activated (66.36 BogoMIPS)
enabling symetric IO mode done
enabling IO-APIC IRQs
IO-APIC pm 0,20,21,22,23,...,255 not connected
MP-BIOS bug: 8254 timer not connected to IO-APIC
trying to set up timer as ExtINT (found pm 0) failed
trying to set up timer as BP IRQ failed
Kernel panic IO-APIC + timer doesn't work
In swapper task not syncing
<hard lock>

The Red Hat manual points out that on an SMP machine, two
kernels are built.  It says the LILO labels are smp and
linux, but they were actually called linux and linux-u.
(Might want to consider syncing the labels and the manual.)
Anyway, linux-u works fine.  If false SMP detection is a
common problem, it might be a good idea to run the
single-processor kernel by default and make those who want
smp choose smp.