Tablet to play with root Part 4 / Extend battery life by clocking down the CPU !?

IMPRESSION KT-i7A4.0 A very rare tablet for domestic use that has root authority in the factory state. For details, refer to the main body review.

CPU clock change application "AnTuTu CPU Master Free Edition" that can be used for free. It can be used only on the root terminal, but there is no problem with KT-i7A4.0.

Last time, I tried to improve the operation by clocking up the CPU, but the clock change application is not only for raising the operating clock. On the contrary, it is also possible to drop the operating clock. Therefore, I decided to check the behavior when the CPU was clocked down.

You might wonder if the CPU clock down doesn't make any sense, even though it's just sluggish. Certainly, not only is it completely meaningless in terms of performance, but it can also be said to be an act that makes the operation even heavier and increases stress during use. However, there is a certain idea there. It extends battery life.

The power consumption of the CPU changes depending on the operating clock. The higher the operating clock, the higher the power consumption, so the clock down reduces the power consumption and lengthens the drive time.

Of course, just because the clock is down does not mean that the battery life will be extended. The CPU installed in the Android device is equipped with a power saving function that controls the operating clock of the CPU core according to the operating status of the device. The Allwiner A10 (ARM Cortex A8) installed in the KT-i7A4.0 also confirms that the clock drops to around 60MHz when idle when observing the operating clock. However, behind the scenes, some process is always running, and the operating clock can go up to 1GHz without any user intervention. In other words, it is considered that there is a good possibility that the battery drive time can be extended by limiting the upper limit clock.

-Under the root environment, important system files can also be edited / deleted, which may cause the tablet to become unstable or not start due to operational mistakes.・ The author, the AKIBA PC Hotline! Editorial department, the manufacturer, and the shop where the product was purchased are not liable for any damages caused by the actions taken by reading this article.・ The author and the AKIBA PC Hotline! Editorial department cannot answer individual questions or inquiries regarding this article.

You can easily clock up with the slide bar. Raise the clock little by little to determine the upper limit clock for stable operation.

● The operating clock has been significantly reduced from 1GHz to 300MHz, and the battery life has been increased by 48 minutes.

Then, using the clock change application "AnTuTu CPU Master Free Version v2.5.2" that I used last time, I set the upper limit of the operating clock to 300MHz and verified the battery drive time.

With the backlight brightness set to the minimum and Wi-Fi turned on, YouTube videos were played continuously using the YouTube video playback application "Youtube Stream", and the drive time in that case was measured.

The results are shown in the table on the right.

● Battery life
Standard clock	About 4 hours and 30 minutes
At maximum clock 300MHz	About 5 hours 18 minutes

It was about 4 hours and 30 minutes in the standard setting state without changing the operating clock, but it was confirmed that the driving time was extended by about 48 minutes to about 5 hours and 18 minutes when the upper limit of the operating clock was set to 300 MHz.

When playing a video, the GPU is the main operation instead of the CPU, so at first I thought that there would not be a big extension of the drive time, but it seems that it will be quite effective if it is extended by this amount. Of course, it doesn't make sense if the clock goes down and the video playback is hindered, but in reality, it could be played back smoothly without any problems, and comfortable viewing was possible.

By the way, the operation of the machine at the time of clock down is really slow, and I get the impression that it is quite difficult to use it regularly. Also, when I checked it with the benchmark application "AnTuTu Benchmark v2.9.2", the score dropped significantly from the standard state.

However, it is not always necessary to clock down the CPU. If you use the clock-up app, you can control the clock freely, so you can use it properly depending on the situation, such as clock-up when performance is required and clock-down when you want to extend the battery life. For example, if you want to enjoy the video for as long as possible while traveling, you can clock it down and use it. This high degree of freedom can be said to be the appeal of the KT-i7A4.0.

Next time, I would like to customize the KT-i7A4.0 to improve its usability.

● Results of AnTuTu Benchmark v2.9.2
Operating clock	300MHz	1GHz	1.104GHz	1.152GHz
Comprehensive	1,511	3,135	3,368	3,472
CPU	250	865	943	986
GPU	1,036	1,372	1,381	1,382
RAM	140	490	534	553
I / O	855	408	510 510	551

□ Rabbit CPU Master (Free Version) (Google Play) https://play.google.com/store/apps/details?id=com.antutu.CpuMasterFree& □ AnTuTu Rabbit Benchmark (Google Play) https: / /play.google.com/store/apps/details?id=com.antutu.ABenchMark&

□ Related article [September 19, 2012] Tablet to play with root Part 3: Overclock the CPU this time, how far will it go up? http://akiba-pc.watch.impress.co.jp/hotline/20120922/sp_review.html [August 30, 2012] Tablet to play with root Part 2: Change Japanese font http://akiba -pc.watch.impress.co.jp/hotline/20120908/sp_review.html [August 30, 2012] Tablet to play with root Part 1: Anyway, first from backup http://akiba-pc.watch .impress.co.jp/hotline/20120901/sp_review.html [August 18, 2012] Not only cheap! A tablet that has already acquired root and can be played thoroughly http://akiba-pc.watch.impress.co.jp/hotline/20120818/sp_review.html

IMPRESSION KT-i7A4.0