ProDigit
Posts: 374
Joined: Tue Aug 30, 2011 1:24 am

Pi 3B+ core throttling at 2A?

Sat Aug 31, 2019 7:46 am

I usually use a 3A charger, however I'm currently using only a 2A charger, a Pi screen hat, and a bluetooth USB puck for keyboard and mouse.

The yellow lightning symbol is on the top right of the screen.

The Pi3B+ now throttles my speed to whatever is set as the 'arm_freq_min' frequency in /boot/config.txt.
Is this normal?

User avatar
rpdom
Posts: 15184
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: Pi 3B+ core throttling at 2A?

Sat Aug 31, 2019 7:51 am

Yes, it is normal. If undervoltage is detect the Pi will throttle back to try and reduce the load.

Get a better Power Supply (not Charger) and make sure you use a decent USB power cable.

ProDigit
Posts: 374
Joined: Tue Aug 30, 2011 1:24 am

Re: Pi 3B+ core throttling at 2A?

Sat Aug 31, 2019 8:30 am

I had set my arm_freq_min to 300Mhz, so it was running quite slow.
It could have easily throttled down to 1,2Ghz instead. But yeah, I have a 3A charger, and don't experience the throttling on it.
I just found it strange for the Pi to throttle down so low on a 2A charger, as there's not really a lot mounted on the Pi, and it should be easily able to throttle to a lot higher.

Ernst
Posts: 1231
Joined: Sat Feb 04, 2017 9:39 am
Location: Germany

Re: Pi 3B+ core throttling at 2A?

Sat Aug 31, 2019 8:43 am

ProDigit wrote:
Sat Aug 31, 2019 8:30 am
I had set my arm_freq_min to 300Mhz, so it was running quite slow.
It could have easily throttled down to 1,2Ghz instead. But yeah, I have a 3A charger, and don't experience the throttling on it.
I just found it strange for the Pi to throttle down so low on a 2A charger, as there's not really a lot mounted on the Pi, and it should be easily able to throttle to a lot higher.
After being a member for 8 years and 320 posts you should by now understand that the bold words above are your problem.
It is not the Amps, it is the inability to deliver sufficient Voltage that is the problem with chargers (and thin leads),
with an official raspberry power supply you would have more satisfaction and less problems.
The road to insanity is paved with static ip addresses

ProDigit
Posts: 374
Joined: Tue Aug 30, 2011 1:24 am

Re: Pi 3B+ core throttling at 2A?

Sat Aug 31, 2019 8:49 am

Ernst wrote:
Sat Aug 31, 2019 8:43 am
ProDigit wrote:
Sat Aug 31, 2019 8:30 am
I had set my arm_freq_min to 300Mhz, so it was running quite slow.
It could have easily throttled down to 1,2Ghz instead. But yeah, I have a 3A charger, and don't experience the throttling on it.
I just found it strange for the Pi to throttle down so low on a 2A charger, as there's not really a lot mounted on the Pi, and it should be easily able to throttle to a lot higher.
After being a member for 8 years and 320 posts you should by now understand that the bold words above are your problem.
It is not the Amps, it is the inability to deliver sufficient Voltage that is the problem with chargers (and thin leads),
with an official raspberry power supply you would have more satisfaction and less problems.
It's not a problem per se.
Just a question if the behavior of the pi was normal.

Return to “Troubleshooting”