ESP32-S3 single core mode power consumption is not lower

[Zoltan Janosy]

I try to reduce the power consumption of an ESP32-S3 by running only a single core. I've checked "Run FreeRTOS on on first core" in the FreeRTOS options. The log shows that the system is indeed running in single core mode, however, the current consumption does not change a bit. According to the datasheet the current consumption should be reduced about 21-22% (modem-sleep, 240 MHz).

Apparently others had similar problems as I have seen similar questions in the forum, but there were no solutions. What else can I try besides setting the option above?

As a related question, I have also tried running the system at a lower clock rate, i.e., at 160 MHz. This does reduce the current somewhat, but way less than stated in the datasheet. The claimed reduction is about 21-25% (modem sleep, 240 MHz vs. 160 MHz), however, I get only about 10%.

I have a custom board built around an ESP32-S3-WROOM-1-N8R2 module, running on IDF 5.1.1. The processor load is about 40%, running some floating point DSP code.

Anyone at Espressif could you please help?

Thanks,
Zoltan