# Chrony comparison - Ubuntu vs FreeBSD

**URL:** <https://community.ntppool.org/t/chrony-comparison-ubuntu-vs-freebsd/4148>\
**Category:** Client Configuration and Development\
**Created:** [November 21, 2025, 6:35pm UTC](https://community.ntppool.org/t/chrony-comparison-ubuntu-vs-freebsd/4148 "2025-11-21T18:35:47Z")\
**Posts on this page:** 4\
**Page:** 3

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**Author:** ![mlichvar](https://avatars.discourse-cdn.com/v4/letter/m/e79b87/32.png) [@mlichvar](https://community.ntppool.org/u/mlichvar)\
**Post date:** [January 5, 2026, 8:48am UTC](https://community.ntppool.org/t/chrony-comparison-ubuntu-vs-freebsd/4148/42 "2026-01-05T08:48:21Z")

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Have you tried disabling CPU power-saving states and setting it to run at a constant frequency? I’m not sure how that can be done on FreeBSD. On Linux there is the `idle=poll` kernel option and the `cpupower` utility.

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**Author:** ![elvisimprsntr](https://avatars.discourse-cdn.com/v4/letter/e/43a26b/32.png) [@elvisimprsntr](https://community.ntppool.org/u/elvisimprsntr)\
**Post date:** [January 5, 2026, 9:15am UTC](https://community.ntppool.org/t/chrony-comparison-ubuntu-vs-freebsd/4148/43 "2026-01-05T09:15:22Z")

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On FreeBSD, I believe it’s called POWERD and CPUFREQ

> **[14.6.2. CPU Power Management - Chapter 14. Configuration, Services, Logging and...](https://docs.freebsd.org/en/books/handbook/config/#cpu-power-management)**
>
> CPU is the most consuming part of the system. Knowing how to improve CPU efficiency is a fundamental part of our system in order to save energy. | This chapter explains much of the FreeBSD configuration files, how to enable or disable a service, how...

pfSense makes it easy

 ![Screenshot 2026-01-05 at 4.10.18 AM](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/f/f5cc13ab61d37be6b668599951cc759c8797856d.png)

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**Author:** ![ccb056](https://avatars.discourse-cdn.com/v4/letter/c/b9e5f3/32.png) [@ccb056](https://community.ntppool.org/u/ccb056)\
**Post date:** [January 16, 2026, 8:24pm UTC](https://community.ntppool.org/t/chrony-comparison-ubuntu-vs-freebsd/4148/44 "2026-01-16T20:24:18Z")

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Here is the latest config:  
changed from SOCK to SHM  
PowerD remains disabled  
dev.hwpstate\_intel.0.epp=0 (as opposed to 50, for maximum performance, resulting in CPU clock being set to 2.4 ghz instead of 800 mhz)  
Offsets had to be updated per below:

```auto
#2026-01-15
# 95% CI: ±0.023µs (n=90134)
# 95% CI: ±0.011µs (n=90181)
# 95% CI: ±0.012µs (n=90174)
# 95% CI: ±0.097µs (n=90147)
refclock SHM 1 refid GPS1 offset +0.000063339
refclock SHM 3 refid GPS2 offset -0.000000149
refclock SHM 5 refid GPS3 offset +0.000000154
refclock SHM 7 refid GPS4 offset +0.000044180
```

Interrupt rate is down to 12 interrupts per second per COM port

 ![image](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/f/f8d1a893f683600736601944f3a8a42b43f103da.png)  
Sending only NAV-PVT and NAV-TIMELS

 ![image](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/8/8cfa25bf6171b066f5dcd1cf095d4e946a0ab992.png)  
 ![image](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/b/b78c590ca3e4b85866c8b2fe899d23ba2189e681.png)  
 ![image](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/2/2eda9488acb0381c2ef80299d16c4f15748cd318.png)

Interesting that the error margin on COM 4 degraded, COM 1 seems to be the same, and COMs 2 and 3 improved

 ![COM 1](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/9/9ea6d1bde9e381d305b2b96933dd45e8fcd2f2fc.png)  
 ![COM 2](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/b/b01a47b925f59858ee4a13f6631959af6307f6ca.png)  
 ![COM 3](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/b/b79aa6de8bb9054c73e972623da39a545c145d80.png)  
 ![COM 4](https://us1.discourse-cdn.com/flex016/uploads/ntppool/original/2X/4/45e3cd85e25f1c5f32a7d8ed82adbd0f25d4df1a.png)

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<div class="post-metadata">

**Author:** ![Mpegger](https://avatars.discourse-cdn.com/v4/letter/m/e19adc/32.png) [@Mpegger](https://community.ntppool.org/u/Mpegger)\
**Post date:** [January 17, 2026, 5:07pm UTC](https://community.ntppool.org/t/chrony-comparison-ubuntu-vs-freebsd/4148/45 "2026-01-17T17:07:48Z")

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Since you are using a U-blox chip and GPSd and trying to reduce serial data packet size, if all you need is time and have no need for location, you can disable all message and only enable the GxZDA (Time & Date) message. All GPSd needs is the current time and date to combine with the PPS pulse to output to Chrony.

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