The raspberry pi5 always stays at 1600mhz in iddle. Shouldn’t it go down to 1500? or less
Then I installed a lenovo dietpi laptop and something similar happens to me, it has the minimum frequency set to 800mhz but it always stays at 2300mhz and the cpu is set to 70c.
BTW: on RPi5, Raspberry developer still working on the whole stuff around voltage and CPU frequency. There are a couple of issues still, we suffer from.
Use piStats in Continuous mode to check the idle frequency.
Even just asking the clock rate will likely get out the Pi 5 from idle; you need to monitor for a few minutes to an half hour and see what is the lowest detected.