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SubjectX9SCM-F-O clock drift +1 second into the future when ntp running?
Date
Hello,

I migrated from an X7SPA to an X9SCM-F-O and now gpsd/ntp no longer sync
with my GPS unit:
http://www.amazon.com/GlobalSat-BU-353-USB-GPS-Receiver/dp/B000PKX2KA

I did some digging and it looks like the system clock on this motherboard
with the latest BIOS (2.00a) runs 1 second too fast when comparing to other
NTP-synchronized machines.

When comparing the clock on this vs. an atomic clock, the system clock is ~1
second faster, which is probably why the GPS has problems syncing.

Is this a faulty motherboard clock or is this an issue with Ivy Bridge (I am
using an E3-1200 V2 CPU) with the X9SCM-F-O and BIOS 2.00a?

DMI Info:

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
Vendor: American Megatrends Inc.
Version: 2.0a
Release Date: 06/08/2012
Address: 0xF0000
Runtime Size: 64 kB
ROM Size: 8192 kB

NTP problem:

Problem, the x127 for the GPS:

$ ntpq -pn
remote refid st t when poll reach delay offset
jitter
============================================================================
==
x127.127.28.0 .GPS. 0 l 11 16 377 0.000 0.363
100.414
*204.235.61.9 128.174.38.133 2 u 48 64 37 48.716 -985.27
326.767
+184.105.192.247 216.218.254.202 2 u 43 64 37 90.902 -987.55
332.766
+50.7.247.114 85.114.26.194 2 u 42 64 37 158.445 -985.19
330.627
+69.65.40.29 209.51.161.238 2 u 43 64 37 47.733 -984.50
329.232

Any idea why it consistently has a ~1 second offset?
Is there a good way to fix this?

Before, on the X7SPA I ran gpsd+ntp for years without any issues, it
synchronized perfectly. Is this a BIOS issue? Kernel problem or HW issue?

$ cat /sys/devices/system/clocksource/clocksource0/current_clocksource
tsc

Full output:

# adjtimex -p
mode: 0
offset: 0
frequency: 1523449
maxerror: 16000000
esterror: 16000000
status: 8257
time_constant: 3
precision: 1
tolerance: 32768000
tick: 10015
raw time: 1341673069s 873569969us = 1341673069.873569969
return value = 5

After 5-10 minutes without ntpd running, the clock had drifted -2.27 seconds
the other direction..

# ntpdate time.nist.gov
7 Jul 11:03:32 ntpdate[374]: step time server 128.138.140.44 offset
-2.273077 sec

Justin.



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