I too thought that using an Oven stabilized crystal oscillator world be the best approach, but as I read on, I realized that doing it entirely in software was an interesting way to go, and well worth the journey.
Most Stable Raspberry Pi? Better NTP with Thermal Management
81–90 of 99 posts
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#82[dead]
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#83I would not have considered artificially-working the SOC to maintain a steady temp! When the wattage is that low, however, it makes sense to burn a few extra bucks a year versus some kind of overengineered cooling system.
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#84[dead]
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#85love this line FTA:
"Is It Worth It?
For 99.999% of use cases: absolutely not."
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#86You can go further and replace the cheap Pi oscillator crystal with a proper TCXO, as others using them for NTD have done and documented: https://raspberrypi.stackexchange.com/questions/74482/switch... That should give you 4-5x less drift than his results (though you could pair the techniques for even better figures)
Believe me, I have read that post/comment quite a few times. There are actually Pi 4 hats for sale for audiophiles (that seem to believe that you need 54000000.000 MHz system clock or whatever it is for Pi4 (Pi3 is 19.2 MHz) for optimal audio) that have an OCXO on them. But in another comment I said I'm not sure my soldering skills are that good.
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#87Earlier quoted context omitted.
In 2025, there are extremely efficient CPUs from Intel and Apple. Under 5W idle! The old Intel CPUs were grotesquely inefficient. Every single generation of Raspberry Pi has been well under 5W idle. And just so it's clear, the author is using an old Raspberry Pi 3. From TFA: > The RPi 3B’s 19.2 MHz oscillator is physically located near the CPU on the Raspberry Pi board, so by actively controlling CPU temperature, we’…
> In 2025, there are extremely efficient CPUs from Intel and Apple. Under 5W idle! I don't think Intel has any "efficient" CPU that can go passively cooled at load though. Maybe Apple can do it for the low end SoCs. The Pi 3 can go passively cooled and maybe even without a heatsink at load, but the newer Pis can't. Judging by the progression from 3 to 4 to 5, they will reach P4 levels of heat in the name of speed aro…
Noctua has a cooler that can handle something like 65W-70W CPUs completely passively. https://www.noctua.at/en/products/nh-p1
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#88You can go further and replace the cheap Pi oscillator crystal with a proper TCXO, as others using them for NTD have done and documented: https://raspberrypi.stackexchange.com/questions/74482/switch... That should give you 4-5x less drift than his results (though you could pair the techniques for even better figures)
Believe me, I have read that post/comment quite a few times. There are actually Pi 4 hats for sale for audiophiles (that seem to believe that you need 54000000.000 MHz system clock or whatever it is for Pi4 (Pi3 is 19.2 MHz) for optimal audio) that have an OCXO on them. But in another comment I said I'm not sure my soldering skills are that good.
I didn't think I was good at soldering until I invested in a good soldering workstation. That is:
* A microscope with a good working distance, and a large screen.
* A soldering iron with very short grip to tip distance. Miniware TS1M with 210/245 tips is a good choice.
* Some proper jigs to hold things. (Stickvise, sliding magnet plates)
* Good extraction so I don't worry about fumes. (Setting up over a stove range hood is great in a pinch)
Also just watching some of the soldering masters at work: https://www.youtube.com/@ycs-yang/videos
I don't have heaps of experience or the steadiest hands, but I'd be comfortable doing a mod like this cleanly now. One good tip is to get your work piece in a position where you can securely rest the blade of your hand on the table or something secure. You want to minimize the leverage and distance between a secure rest point and your work tip.
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#89Austin from austinsnerdythings.com here! Posted this last night and went to sleep. Definitely didn't expect to wake up to it #1 on HN this morning! Some notes that weren't included in this post: I do have my LEA-M8T generating time pulses at 16 Hz, with a dpoll of -4 in the chrony config. The poll interval of 16 seconds means it gets 256 samples which also improved the stability. I do also have that mentioned BH3SAP…
Thanks for writing this up! I have a similar setup, largely based on your earlier post. I'm looking forward to trying out some of these ideas.
Do 16Hz pulses make much difference? I found conflicting information and haven't yet tried it myself.
What do you use to get the data into influxdb? I'm using collectd but it doesn't gather a lot of useful info.
Re: Most Stable Raspberry Pi? Better NTP with Thermal Management
#90[deleted]