RPi 3 A+ DietPi-Config Performance Options Topic is solved

[@lone]

Good morning

I'm a DietPi user (7 RPi's and 1 Asus TB). I use it to crunch BOINC Universe@Home data.

Last DietPi update (v6.30.0) introduced a problem for my 4 RPi's 3 A+. Performance Options presented in DietPi-Config for these computers are exactly the same as for RPi's 3 B ['none' option is 1200 MHz and 'high' is 1350 MHz (please check attached images DietPi@RPi3A+.png and DietPi@RPi3B.png)), nowhere near RPi 3 A+ hardware base frequency: 1400MHz].

CPU utility reports same values for RPi's 3 A+ as chosen in DietPi-Config's Performance Options.

Can you please confirm if this is normal or if I'm missing something. I try to get best performance from my RPi's and ATB.

Thank you.

Best regards,

Paulo Reis

[MichaIng]

Many thanks for your report.

There is indeed a bug in the code that does not detect RPi 3+ devices correctly. Looks like I missed the "(armv7l)" suffix in device name...
Please do:

Code: Select all

sed -i "s/\*'+' /*'+'* /" /boot/dietpi/dietpi-config

That should recover the overclocking options for RPi 3+, although note that we never head any profile for those so only "none" with stock clock is presented. However you can edit /boot/config.txt and adjust the overclocking parameters there. Not sure if there was a reason for no pre-set (I guess we just followed raspi-config), however if you find a stable mode that does not increase CPU temperature regularly >75°C, let me know and I can add it to dietpi-config.

[MichaIng]

Fixed: https://github.com/MichaIng/DietPi/comm ... c82b669652

[@lone]

Good afternoon,

Thank you for your quick reply, and specially for DietPi.

I will test some RPi 3 A+ CPU settings and come back to you.

Best regards,

Paulo Reis

[@lone]

Good morning,

As promised, here are results from my RPi 3 A+ overclocking tests.

I made over 20 tests ranging from “1400 MHz with -2 over voltage option” to “1500 MHz with 1 over voltage option”. No other changes were made to other parameters.

Only two tests provided stable RPi 3 A+ operation:
a) 1450 MHz with 0 over voltage (3,57 % overclock);
b) 1475 MHz with 0 over voltage (5,36 % overclock).

Stability of case a) was achieved in all 4 RPi 3 A+. Case b) was only stable in 2 of my RPi 3 A+. Please check “RPi 3 A+ Overclocking Feedback a.png” for detailed information.

Images “RPi 3 A+ Overclocking Feedback b.png”- general info -, “RPi 3 A+ Overclocking Feedback c.png” - CPU Loads info - and “RPi 3 A+ Overclocking Feedback d.png” - Temperature info - provide detailed information gathered from RPi-Monitor running on my “RPi 3 A+ A @ 1475 MHz with 0 over voltage”. This machine is running without any problems from 2020/07/26. “CPU Loads” and “Temperature” drops on the 2020/08/10 are due to maintenance reboot. Similar behavior can be verified for my “RPi 3 A+ B @ 1475 MHz with 0 over voltage” and for my “RPi 3 A+ C and D both @ 1450 MHz with 0 over voltage”

Operation temperature is around 50º C. Temperature values change over time reflect decrease of room temperature. This operation temperature is achieved by using 5 cm fan operating over RPi 3 A+ cpu (using adapted RPi case). No tests were done without fan operation so, no temperature limit check was done for all tests made.

RPi 3 A+ run BOINC software for Universe@home project. All 4 cores run at full speed 24h / day. RPi 3 A+ display circuitry is switch off (running /usr/bin/tvservice -o) on all RPi’s.

During my tests some conflicting CPU speed information was provided by different tools:
1) DietPi-Config (please check image “RPi 3 A+ CPU Speed.png”) reports CPU speed defined in “/boot/config.txt” (please check image “RPi 3 A+ CPU Speed.png”);
2) Same speed is reported by RPi-Monitor (please check image “RPi 3 A+ Overclocking Feedback b.png”);
3) lscpu and DietPi CPU utilities report 1500 MHz (please check image “RPi 3 A+ CPU Speed.png”). lscpu is probably reporting CPU spec and not current operation speed (it does the same for my ASUS TB) but RPi 3 A+ base spec is 1400 MHz. DietPi CPU reports current CPU operation speed in all my other RPi’s and ASUS TB.

I have no knowledge to verify the cause of this behavior, present in all RPi 3 A+ (running at 1450 MHz and 1475 MHz).

RPi 3 A+ is a wonderful little board but is very sensible to changes in CPU speed (not due to temperature, but to system stability, from my experience). 3,57 % or 5,36 % is almost no overclock.

I hope this information is useful.

Best regards,

Paulo Reis

[MichaIng]

Jep, DietPi v6.31 solved the bug that showed RPi 3 non-plus overclocking profiles on RPi 3+ models.