Rock64 ARM Single Board Computer

Was looking for a 64-bit ARM based quad-core Single Board Computer (SBC) with at least 4GB of RAM around the $50-60 price point. After doing some research, zero'd in on Rock64. Each core was supposed to be 1.5Ghz. On booting Armbian (at least version 5.75), realized each core was running at 1.39Ghz instead of the advertised 1.5Ghz. The following are the steps to steps to tweak Rock64 to run at the desired clock speed:

Determine the release/version of the Armbian Linux operating system by executing the following command:

$ cat /etc/armbian-release

The following would be the typical output:

Output.1

# PLEASE DO NOT EDIT THIS FILE
BOARD=rock64
BOARD_NAME="ROCK64"
BOARDFAMILY=rockchip64
VERSION=5.75
LINUXFAMILY=rockchip64
BRANCH=default
ARCH=arm64
IMAGE_TYPE=stable
BOARD_TYPE=conf
INITRD_ARCH=arm64
KERNEL_IMAGE_TYPE=Image

Check the clock speed of each CPU core by executing the following command:

$ cpufreq-info -c 0

The following would be the typical output:

Output.2

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: cpufreq-dt
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0 1 2 3
  maximum transition latency: 80.0 us.
  hardware limits: 408 MHz - 1.39 GHz
  available frequency steps: 408 MHz, 600 MHz, 816 MHz, 1.01 GHz, 1.20 GHz, 1.30 GHz, 1.39 GHz
  available cpufreq governors: interactive, conservative, userspace, powersave, ondemand, performance
  current policy: frequency should be within 600 MHz and 1.39 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1.39 GHz (asserted by call to hardware).
  cpufreq stats: 408 MHz:0.04%, 600 MHz:77.14%, 816 MHz:0.74%, 1.01 GHz:0.36%, 1.20 GHz:0.05%, 1.30 GHz:0.08%, 1.39 GHz:10.03%, 1.51 GHz:11.56%  (195)

As is evident from Output.2 above, we see the current clock speed at 1.39Ghz

Check the current settings for the CPU clock frequency by executing the following command:

$ cat /etc/default/cpufrequtils

The following would be the typical output:
Output.3
```
# WARNING: this file will be replaced on board support package (linux-root-...) upgrade
ENABLE=true
MIN_SPEED=600000
MAX_SPEED=1390000
GOVERNOR=ondemand
```
Bump the maximum CPU clock frequency to 1.5Ghz by executing the following command:

$ sudo sed -i "s/MAX_SPEED=.*/MAX_SPEED=1512000/" /etc/default/cpufrequtils
To immediately enable the updated CPU clock frequency to 1.5Ghz, execute the following command:

$ sudo systemctl restart cpufrequtils

Now, check the clock speed of each CPU core by executing the following command:

$ cpufreq-info -c 0

The following would be the typical output:

Output.4

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
  driver: cpufreq-dt
  CPUs which run at the same hardware frequency: 0 1 2 3
  CPUs which need to have their frequency coordinated by software: 0 1 2 3
  maximum transition latency: 80.0 us.
  hardware limits: 408 MHz - 1.51 GHz
  available frequency steps: 408 MHz, 600 MHz, 816 MHz, 1.01 GHz, 1.20 GHz, 1.30 GHz, 1.39 GHz, 1.51 GHz
  available cpufreq governors: interactive, conservative, userspace, powersave, ondemand, performance
  current policy: frequency should be within 600 MHz and 1.51 GHz.
                  The governor "ondemand" may decide which speed to use
                  within this range.
  current CPU frequency is 1.51 GHz (asserted by call to hardware).
  cpufreq stats: 408 MHz:0.04%, 600 MHz:77.14%, 816 MHz:0.74%, 1.01 GHz:0.36%, 1.20 GHz:0.05%, 1.30 GHz:0.08%, 1.39 GHz:10.03%, 1.51 GHz:11.56%  (195)

As is evident from Output.4 above, the current clock speed at 1.5Ghz

Output.1

Output.2

Output.3

Output.4

ATTENTION: