Freebsd 6.0 doesnt detect local APIC on a Pentium 3 machine

hi,

FreeBSD 6.0 always uses local APIC for the clock.

But on my Pentium 3, 850 MHz machine, it doesnt detect local APIC and
falls back to using the motherboard clock for the clock interrupts.

I figured this out by printing the value of 
"using_lapic_timer" variable in the sys/i386/isa/clock.c file,
which is always 0.

But when I use Intel's 3GHz - 64 bit Xeon processor, it detects local APIC
and all works fine.

Can someone please tell me the reason, why local APIC doesnt work for the 
Pentium 3 machines ? Or is there a way to fix this ?

Thanks
vaibhave