cpu0: Intel Pentium Pro, II or III (686-class), 598.10 MHz, id 0x6d6
  cpu0: features afe9f9bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,SEP,MTRR>
  cpu0: features afe9f9bf<PGE,MCA,CMOV,PAT,CFLUSH,DS,ACPI,MMX>
  cpu0: features afe9f9bf<FXSR,SSE,SSE2,SS,TM,SBF>
  pci0 at mainbus0 bus 0: configuration mode 1

  It should be 1.7GHz. 

Did you boot it while on battery?  This almost certainly has 'enhanced
speedstep' or something, and there is some way (ACPI I think) to
adjust the CPU speed.  I believe the default at boot is full if on
power and low if on battery, and then the BIOS expects the OS to
control this.  Some FreeBSD folks have added support for adjusting the
speed after boot depending on the load average:

http://www.daemonology.net/freebsd-est/


-- 
        Greg Troxel <gdt@ir.bbn.com>