I'm seeing this in my logs about 30 times a day, from what I gather  
from a little googling this is not normal behavior. The system in  
question is a GX260 (ICH4 i865) using TSC for time counters. Should I  
make like what others have reported and switch to i8254 and erase the  
drift file? I have one stratum 1 and 4 stratum 2 servers in my ntp  
conf file.

Jul  9 04:02:09 pylon ntpd[8624]: kernel time sync enabled 6001
Jul  9 04:53:22 pylon ntpd[8624]: kernel time sync enabled 2001
Jul  9 06:01:37 pylon ntpd[8624]: kernel time sync enabled 6001
Jul  9 06:35:45 pylon ntpd[8624]: kernel time sync enabled 2001
Jul  9 07:26:58 pylon ntpd[8624]: kernel time sync enabled 6001
Jul  9 07:44:02 pylon ntpd[8624]: kernel time sync enabled 2001
Jul  9 08:18:13 pylon ntpd[8624]: kernel time sync enabled 6001
...


NetBSD pylon 3.99.21 NetBSD 3.99.21 (GENERIC.MPACPI) #1: Tue Jun 13  
11:23:48 EDT 2006


timecounter: Timecounters tick every 10.000 msec
timecounter: Timecounter "i8254" frequency 1193182 Hz quality 100
timecounter: selected timecounter "i8254" frequency 1193182 Hz  
quality 100
BIOS32 rev. 0 found at 0xffe90
mainbus0 (root)
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel Pentium 4 (686-class), 2524.10 MHz, id 0xf24
cpu0: features  
3febfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR>
cpu0: features 3febfbff<PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX>
cpu0: features 3febfbff<FXSR,SSE,SSE2,SS,HTT,TM>
cpu0: "Intel(R) Pentium(R) 4 CPU 2.53GHz"
cpu0: I-cache 12K uOp cache 8-way, D-cache 8 KB 64B/line 4-way
cpu0: L2 cache 512 KB 64B/line 8-way
cpu0: ITLB 4K/4M: 64 entries
cpu0: DTLB 4K/4M: 64 entries
cpu0: enabling thermal monitor 1 ... enabled.
cpu0: calibrating local timer
cpu0: apic clock running at 132 MHz
cpu0: 16 page colors
ioapic0 at mainbus0 apid 8 (I/O APIC)
ioapic0: pa 0xfec00000, version 20, 24 pins
ioapic0: misconfigured as apic 0
ioapic0: remapped to apic 8
acpi0 at mainbus0: Advanced Configuration and Power Interface
acpi0: using Intel ACPI CA subsystem version 20060217
acpi0: X/RSDT: OemId <DELL  , GX260  ,00000009>, AslId <ASL ,00000061>
acpi0: SCI interrupting at int 9
acpi0: fixed-feature power button present
mpacpi: could not get bus number, assuming bus 0
...
ioapic0: enabling
timecounter: Timecounter "TSC" frequency 2524058240 Hz quality 800
timecounter: selected timecounter "TSC" frequency 2524058240 Hz  
quality 800
timecounter: Timecounter "clockinterrupt" frequency 100 Hz quality 0


kern.timecounter.choice = clockinterrupt(q=0, f=100 Hz) TSC(q=800,  
f=2524058240 Hz) i8254(q=100, f=1193182 Hz) dummy(q=-1000000,  
f=1000000 Hz)
kern.timecounter.hardware = TSC
kern.timecounter.timestepwarnings = 0