Hi,
The machine started life as a 7600/132 - for example, that's what's printed on the case - but (I'm told) it's got a G3 upgrade in it. dmesg.boot describes the CPU thus (I am not comptent to say whether this means it really is a G3 or not, which is why I put it that way): cpu0 at mainbus0: 750 (Revision 2.2), ID 0 (primary) cpu0: HID0 8090c0a4<EMCP,DOZE,DPM,ICE,DCE,SGE,BTIC,BHT>, powersave: 1 cpu0: 305.89 MHz L2 cache present but not enabled
You can find out more about your CPU card from this page: http://www.lowendmac.com/ppc/g3card.shtml
The time it keeps is wrong by almost a percent - it runs approximately half a second per minute slow. ntp fails to sync under these circumstances (yes, I did check for an old ntp.drift file; this is being tested after destroying ntp.drift). Killing ntpd and running ntpdate -b once a minute produces matching results (a correction of about .48 seconds each time around). Any ideas? I can provide more details, if you can tell me where to find them....
I would have to guess that your machine is anomalous. I have several 7300 - 7600 type machines, 4400, Performa 6400, 9600, first generation iMac, various G4 towers, with a variety of accelerator types, and I've never seen any time drift issues. My Motorola StarMax (4400 type) even runs as a stratum 1 timeserver with no problems:
john% ntpq -p grittykitty.ziaspace.com
remote refid st t when poll reach delay offset jitter
==============================================================================
*GPS_NMEA(0) .GPS. 0 l 55 64 377 0.000 0.008 0.008
-clock.isc.org .GPS. 1 u 933 1024 377 17.506 -7.149 0.015
+clock.sjc.he.ne .CDMA. 1 u 26 1024 377 18.115 0.965 0.057
+clock.via.net .GPS. 1 u 947 1024 377 16.607 0.345 0.289
You might just have to fudge your ntpd config.
John