Safely overclocking a V4 unit

Hi Zynthianers,

Is anyone running - with stable hardware behaviour - a 2020 official V4 kit at full 2 GHz overclock?

I am wondering if the Zynductor heat bridge would manage to keep the 4 CPUs at safe temperatures, without damaging the cores or sending them in heat protection lock, each time a substantial audio processing occurs.

In order to possibly attempt the overclocking, I am switching from the mainstream Raspi 4 PSU (5.1 v, 3A) to a more robust 4A.

What I obviously aim to is squeezing a bit more of computational power, to allow for complex multitimbral snapshots without occasional x-runs.
I already set the Zynthian audio at a buffer of 512 frames, when I use it for Midi programming and composition, with an acceptable balance between cleaner performance and a still viable playing latency.

Would my needs benefit significantly, from trying the 2Ghz CPU speed instead of the current 1.5 GHz medium overclocking?

I’m don’t know if you’re already aware, the upcoming V5 Zynthian kit has more serious heat sinking to support 2GHz overclocking:

Thanks @tunagenes,

I am indeed informed about the forthcoming new V5, and very much looking forward to it.

However, my question concerned an existing V4.0 official kit, which I will keep as a parallel instrument for sharing the Midi and audio burden.

Since I see that a full overclocking option has been added to the Webconf, I was wondering if it is reserved for very bespoke builds - with active cooling or whatever -, or it is also feasible to switch on for V4 units.

Well, at the risk of stating the obvious, I think that the new feature:

Mechanized Aluminum Thermal Block => Acts as a massive heatsink that connects the RBPI’s hot surfaces to the aluminum chassis, allowing overclocking up to 2GHz without problems.

implies that with a mere Zynductor you may overclock to 2 GHz, but with problems! Depending on ambient temperature, the specific CPU you happened to get in your RPi, the phase of the moon, etc.

I can understand that you’d like to hear from people who have overclocked to 2 GHz successfully with Zynductors only (I would too), so I guess we’ll see if we hear anything besides crickets.



:sunglasses: You have evidently a point, in stressing that we all would be glad to get the green light for hard overclocking from someone else, who hopefully has bravely gone where nobody has before in our place, possibly risking to barbecue the valued Rpi precious in the process!

I also thought that a logical comparison between the new mechanised heat sink, as announced in V5, and the alluring but not default option of 2Ghz clock in V4 should lead us to deduce that meddling with the CPU speed of the current hardware is a somewhat experimental and under-our-responsibility procedure.

In the purview of such premises, I think that I will keep prudently the medium clock, or maybe just attempt some sparse excursions, carefully surveilling the cores’ temperature in the control panel…



If you have V4, you could use overclocking carefully, given that the zynductor is well installed. If ambient temperature is low-enough you shouldn’t have problems when using maximum speed (2GHz), but be warned that you probably would have problems if ambient temperature goes beyond 20ºC.

If you keep an eye on system temperature by refreshing webconf’s dashboard, you could change to a lower overclocking profile when temperature goes higher than 60-65ºC.

FYI, with the V5’s massive heatsink, zynthian runs at 2GHz flawlessly with high ambient temperatures over 30ºC. The case becomes hot, but CPU temperature never goes beyond 50ºC. Super-Cool!!!


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Hi @jofemodo,

Thanks for your specific feedback on my query, which has been kindly forwarded by @tunagenes.

I appreciate that given the average, yet significant, heat-sinking functionality of the V4 Zynductor, overclocking the CPU to the upper limit would require optimum environmental conditions, and constant temperature monitoring. Since we are now fully in Spring, and soon heading to the summer, I will maintain a “conservative” position about the clock, unless I happen to concoct unusually demanding multitimbral setups, with heavily layered chains of instruments and effects.

By the way, I have verified that raising the buffer to 512 frames already improves the audio performance considerably, at the sacrifice of just a bit of added latency. I look forward to the V5, for being able to push the Zynthian to full throttle! (with an added unit of backup for extended multichannel functionality).

Regards :slightly_smiling_face:

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