What is an overclocked raspberry pie?
Overclocking is the most convenient way to increase the performance of computer hardware free of charge. Specifically, it refers to raising the rated frequency of CPU, video card, memory and other hardware devices to a certain extent so that they can operate at higher frequencies to achieve better performance. Therefore, overclocking is also considered to be a manifestation of DIY players' skill level, and is also a measurement index of DIY manufacturers' R&D foundation.
That's specific to the Raspberry Pi. How should I overclock the device? However, before specific operations, I must first select the selected device. The current market is more popular is the Raspberry Pi 3 and Raspberry Pi 2 models. Since the Raspberry Pi3 performs better than the Raspberry Pi2 in all aspects, I can obtain more power through overclocking and overvoltage techniques. However, since the basic technical characteristics of the two models are similar, the Raspberry Pi 3 overclocking technology is also applicable to the Raspberry Pi 2, but the effect of overclocking will be greatly reduced.
In short, overclocking is a way to improve the performance of Raspberry Pi hardware by adjusting multiple device parameters. To do this, additional hardware and special operating skills are required.
If you want to know which projects use the overclocked Raspberry Pi, you can find relevant information at the end of this article, or consider using the ExaGear Desktop software for testing. Also, keep in mind that you need to perform multiple tests to ensure the changes take effect and the device is not damaged.
Overclocking can improve the performance of your computer. What are the preparatory tasks for overclocking?
The first is a good hardware system. The CPU, memory, and graphics cards must all be healthy. Working at 100% load can also have reasonable temperature and power consumption.
The second is the hardware preparation, overclocking requires a strong motherboard to support, especially the motherboard power supply, taking into account the CPU and memory overclocking power consumption, high and low signal requirements can not be fuzzy, so the motherboard power supply must reach 4 + 1 or higher, so that the pressure of each power supply is small.
Finally, overclocking requires a powerful heatsink and power supply. The former allows the CPU and graphics card to operate at a reasonable temperature to improve the stability of overclocking and overclocking processes. The latter can give the hardware sufficient power support, even if the power consumption increases. response.
This means that when you overclock your Raspberry Pi3, there are some risks. So specifically what are these risks and how can they be avoided?
Overclocking related risk warnings
Warning 1
Currently, there is no official support for overclocking Raspberry Pi3, so you may damage your device. So, first advance life. If you break the raspberry pie with reference to my method, I will not be responsible. So important things to say three times, please be cautious before overclocking!
Warning 2
Overclocking may warm up the hardware to near 90°C. This may cause the program to crash, CPU damage, and memory chip damage. To prevent this, the heat dissipation of the chip must be very good. Because fans increase the cooling effect, they are highly recommended. So say something important three times and don't overclock without cooling.
Extra hardware required for overclocking
If you want to overclock your Raspberry Pi, you need to configure three important hardware accessories:
1. Raspberry Pi, this article I used a Raspberry Pi 3 model B V1.2 running with Raspbian GNU/Linux 8 (Jessie).
2. Power supply It is highly recommended to use a reliable power supply. The overclocked Raspberry Pi 3 can be used for currents of 1.5A or more. Therefore, this article uses 2A for overclocking.
3. Cooling equipment, in order to prevent the Raspberry Pi equipment from overheating, I must find the fan and radiator.
Important: You can use the following command to upgrade the installed packages to the latest version:
$ sudo apt-get update && sudo apt-get dist-upgrade
At the beginning and end of the process, you need to check the system performance. You can use the "sysbench" tool to do this easily. It can be installed with one of the following commands.
$ sudo apt-get install sysbench
As shown in the figure below, it is all the overclocking equipment I need.
In detail, it is:
1. Raspberry Pi 3;
2. The power supply voltage is 5 volts and the current is 2500 mA.
3. A built-in fan;
4. Three heat sinks;
5. A base with memory cooling space and fan space.
The following figure is a schematic diagram of the equipment after I assembled it:
Please note that in this picture, the largest radiator is under the fan, and the copper radiator is at the bottom of this picture.
Pre-overclocking routine inspection
However, before I started to overclock the Raspberry Pi, I had to prepare and check some overclocking conditions.
Monitor CPU frequency
To understand the current CPU operating frequency, I must read the proc files cpuinfo_min_freq, cpuinfo_max_freq, and cpuinfo_cur_freq from / sys / devices / system / cpu / cpu0 / cpufreq / directory, where:
Cpuinfo_min_freq represents the minimum frequency of the "idle" mode;
Cpuinfo_max_freq represents the maximum frequency;
Cpuinfo_cur_freq represents the current operating frequency of the Raspberry Pi.
Monitor CPU temperature
To know the current CPU temperature, I can run the vcgencmdmeasure_temp command. Also, to observe the temperature every second, I can run it in a "while" loop like this:
$ while true ; do vcgencmd measure_temp ; sleep 1 ; done
This loop starts running until I terminate it with CTL + C.
Set the default speed
The default CPU configuration of the Raspberry Pi board is in idle mode without a task, as follows:
Arm_freq = 600 mhz
Core_freq = 250 mhz
If the process is running, the frequency will rise to:
Arm_freq = 1200
Core_freq = 400 (this is the maximum default value for Raspberry Pi3).
To prevent Idle mode from being broken, I must set these following lines in /boot/config.txt:
Force_turbo = 1, note! Changing this parameter will automatically cancel (warranty)
Boot_delay = 1
After that, restart your Raspberry Pi and check the current operating frequency again. It should now be set to 1200000KHz.
Perform Raspberry Pi Performance Test without Overclocking
For the first performance test, I ran the following command.
$ sysbench --test=memory --cpu-max-prime=2000 --num-threads=4 run
The output is as follows:
At this point, the normal test of the Raspberry Pi 3 is over.
How to Overclock Your Raspberry Pi 3
Raspberry pie overclocking options
The overclocking configuration is set in the /boot/config.txt file. To overclock, I only need to set various system configuration parameters in this file. There are 6 ways to achieve overclocking:
1. Overclocking Raspberry Pi CPU, which means changing the "arm_freq" parameter - ARM's frequency in MHz.
2. Overclocking the Raspberry Pi GPU, which means changing the "core_freq" parameter - the frequency of the GPU processor core in MHz. Because it drives the L2 cache, it has an impact on the ARM's performance;
3. Overclocking Raspberry Pi memory, which means changing the "sdram_freq" parameter - SDRAM frequency in MHz;
4. Additional extension of Raspberry Pi memory, which means ZRAM is used to compress memory (see below for details);
5. Additional overclocking parameter "Over_voltage", which is the ARM/GPU core voltage adjustment. Values ​​above 6 are allowed only if the "force_turbo" or "current_limit_override" parameters are specified (set in the warranty bit);
6. Additional overclock parameter "Force_turbo", this parameter disables the dynamic cpufreq driver and requires the following minimum settings, at which point the authorization is invalid.
Before you begin to change any parameters, make sure that the /boot/config.txt file is backed up.
Because the performance of different types of raspberry pie varies, you can only determine the correct value by trying various parameters. This means that the best value for each Raspberry Pi must be tested on its own device to find out.
Problems with overclocking
Most overclocking problems will be displayed immediately when they occur and will be suspended. If this happens, hold down the "shift" key the next time you start it. This will temporarily disable all overclocking, allow you to start, and then edit the corresponding settings.
Overclocking method
With this method, you can know how to adjust CPU, GPU, and memory frequency values ​​to get better performance. This also includes adjusting the "over_voltage" parameter, which aims to make the overclocking hardware work stably. Another way is to overclock your Raspberry Pi 3 by adjusting the memory frequency. At this point, I will use ZRAM for monitoring. So, I just do the following:
1. The following is the default value of Raspberry Pi:
Arm_freq=1200
Gpu_freq=400
Core_freq=400
Sdram_freq=450/pre>
Over_voltage_sdram=0
2. In this way, I can write the following configuration to the /boot/config.txt file and restart the Raspberry Pi.
Arm_freq=1300
Gpu_freq=500
Sdram_freq=500/pre>
Over_voltage_sdram=0
3. If the Raspberry Pi is up and running, I can further try the next configuration by raising the value of arm_freq to 1500, saving and restarting.
4. If your Raspberry Pi does not start or runs erratically, calculate the value of over_voltage_sdram until Pi is working properly.
5. If adjusting over_voltage_sdram does not help stabilize your Raspberry Pi's operation or even start it, you must reduce the arm_freq value until the Raspberry Pi runs again. Also, be aware that you must restart your system after every change to the /boot/config.txt file.
How to overclock ZRAM
The ZRAM method is an additional option to increase the performance of the Raspberry Pi device. This method will require you to expand the memory. Overclocking can be done using ZRAM that compresses the internal memory.
ZRAM uses compression algorithms LZ4 and LZO, where LZO is the default value. This algorithm creates a block device that can be used for swapping or as a general-purpose RAM disk.
How to load ZRAM? Since ZRAM is already integrated into the Linux kernel, I just need to use the command sudomodprobezram to load the module. To check if the ZRAM module is running, execute the command sudolsmod| grep ZRAM shown below.
If I want to optimize ZRAM for Raspberry Pi, I can get the script zram.sh from GitHub. The script creates an additional compressed RAM swap disk for each CPU core and activates them without further configuration.
You can use the following command to download the script:
Sudo wget -O /usr/bin/zram.sh https://raw.githubusercontent.com/novaspirit/rpi_zram/master/zram.sh
Then make it executable as shown below.
Now, look at the memory information before activating ZRAM. The free -h and swap -s commands show that I only activate 100MB of swap space in the Raspberry Pi.
Now I can run ZRAM with the command:
Sudo zram.sh
The script will generate a swap space of about 232 MB per CPU core. If I check again with the free -h command, it will show that the swap space has increased to 1GB.
By running swap -s again, I can see that there are four additional swap space partitions created and running.
In order to set the Raspberry Pi to autorun ZRAM at startup, I must edit the /etc/rc.local file and insert /usr/bin/zram.sh& line before exiting line 0. Then you can check the end of the /etc/rc.local file.
After restarting the Raspberry Pi, the logo with ZRAM memory is configured. However, I still have to check again using the free -h and swap -s commands to ensure ZRAM is up and running.
Performance Test in Overclocking State
Now, after I complete the overclocking of the Raspberry Pi, I hope to perform a performance test on the Raspberry Pi again to see if the device is normal. For this reason, I will run the following command again.
Sysbench --test=memory --cpu-max-prime=2000 --num-threads=4 run
The output is as follows:
As you can see, all the test values ​​are better than when they were not overclocked. In the above figure, the green marked value is the running value when it is not overclocked.
How to remove overclocking
If you want to remove the overclock from the Raspberry Pi, just delete the changes from the /boot/config.txt file. If you do this by creating a backup file, simply copy it back to the /boot directory and overwrite the config.txt file.
In addition, you must remove the /usr/bin/zram.sh& line from the /etc/rc.local file. Then restart the Raspberry Pi and all overclocking configurations will be disabled.
to sum up
Now I have successfully overclocked my Raspberry Pi device and can begin to do different interesting projects on this accelerated ARM device.
In addition, many people want to know what their overclocking Raspberry Pi 3 can be used for?
First of all, if your Raspberry Pi runs stably after overclocking, then you will certainly get better device performance and speed, which is not very good. For example, you can try to run x86 applications with higher technical requirements and run heavy workloads, such as mass operations. To run x86 applications on Raspberry Pi and other ARM devices, you also need additional software, such as Exagear Desktop combined with Wine. You can find many examples on my blog, such as:
1. The Plex Media Server on the Raspberry Pi. In this case, I installed and started Plex to manage the media integration application on the Raspberry Pi.
2. Run Spotify on the Raspberry Pi. This case contains the storage, transfer, and management of music (audio) files on the Raspberry Pi. It can serve as a stable and inexpensive music storage server.
3. Run Dropbox on Raspberry Pi, Dropbox on Raspberry Pi will build your own file storage and smart backup system for your project files.
4. The TeamSpeak 3 server (voice server) on the Raspberry Pi. If you are a player (or a player team) then this case will create an audio communication environment for your team.
5. The Raspberry Pi on Google Chrome, this case describes the complex task of installing and running Google Chrome on Raspbian, which can be used for tasks that other open source browsers cannot.
6. Netflix on the Raspberry Pi, this is a good example of Google Chrome browser usage. Netflix can run better with this browser. However, it is quite difficult to implement the technology. In fact, running an application like Netflix on a Raspberry Pi is difficult without overclocking.
7. Make use of Raspberry Pi + RetroPie as a nostalgic game machine. Occasionally you will miss the days of playing bullies with your friends. At that time, few people have a game console at home. There are several friends waiting for a game machine. There are not many things to play at that time, but the days are simple and happy. Although Almighty Taobao can also buy a bully game machine, it is far from being as strong as a sense of accomplishment.
Also, please note that Exagear Desktop can run almost any x86 application on the Raspberry Pi and other ARM-based devices, including but not limited to Odroid, Banana Pi, Beagleboard, Cubox, Jetson, Cubieboard, etc.
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