9 Jan 2021, 01:48

I am observing really strange behavior when I am applying overclock in Recalbox using Pi 4 4GB and looks like @sergioad report confirms my findings.

If I set values below in config.txt

arm_freq=2000
gpu_freq=750
over_voltage=6

then I am getting correct cpu clock when checking back using terminal and framerate especially in PSP games is noticeably better

# vcgencmd measure_clock arm
frequency(48)=2000531200

But if I set maximum allowed Pi 4 OC like this

arm_freq=2147
gpu_freq=750
over_voltage=6

then I am getting only 600 MHz when checking back using terminal, that is significantly lower cpu clock than stock value and it confirms @sergioad report. Emulation is slow like hell in this case. I am using Pi Case 40 from Cooler Master and temps are below 60°C all time and boosting over_voltage is not helping at all.

# vcgencmd measure_clock arm
frequency(48)=600169920

I tried to update to last stable eeprom released 2020-09-03, then applied maximum OC using same method in newly installed Raspberry Pi OS and it was working like charm. Reported clocks were correct and stable. I was testing stability using synthetic load (sysbench) on all 4 cores and temperature did not exceed 65°C after 20 mins of continuous stress testing.

When I returned back to MicroSD card with Recalbox, then I got same strange behavior when applying max. OC. It looks like overclocking in Recalbox still have some issues and needs some tuning by devs.

But overall I am really satisfied with this OS. UX is on totally different (better) level compared to for example RetroPie.