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CPU clock speed and device temperature

A few weeks ago, I bought a MK809III TV-stick Android device from a Chinese store. It’s quite powerful, with 2GB of RAM. Most important, it comes with a RK3188 28nm Cortex-A9 Quad core 1.4ghz clock speed, one of the most powerful chips available in the market for this type of devices.

mk809iii TV stick - 1.2Ghz clock speed

As soon as it got home, I started playing with it. However, that’s when problems begun. After I downloaded a few apps from Google Play, the stick started to reset itself in an apparent random way for no apparent reason.

However, when I removed it from the back of the TV, I noticed the device was hotter than it was supposed to. I know I shouldn’t have but I opened the case searching for any anomalies or dirt cluttering up the cooling vents. Surprisingly, I found nothing except that the seller changed the RK3188 CPU was replaced by a similar one, a RK3188T.

Increasing clock speed beyond design limits

The RK3188T runs at a lower CPU clock speed and hence, its performance is lower. Basically, it’s a cheaper chip. But why was it running hot? The seller was using an overclocked ROM to make it look like it was using the faster chip. Therefore, it was making it run beyond its design limits and this raise the temperature a lot. In other words, running the chip at a faster rate caused the resets.

After looking around a bit, I found about AnTuTu CPU Master, an Android app to control a device’s CPU clock speed. The software requires rooting the device to allow apps to run as a superuser and get full control of the device. after that, you’re ready to go.

AnTuTu CPU Master is designed to control the CPU and GPU clock frequencies in your Android smartphone, tablet or TV stick. It can set a maximum clock-frequency for your Android phone, so that it does not run the CPU beyond that speed. On one hand, this keeps the device cool. On the other, this saves power, making your device’s battery last longer.

You can choose a “scaling mode” from one of the following: userspace, powersave, hotplug or performance. Each of these scaling modes offer the performance level their names imply. Moreover, you can also make CPU Master set these options at every boot of the system.

Similarly, you can limit GPU’s clock speed for your smartphones. This option is available under the “Advanced” section of the app. Keep in mind that it may not work on all phones because of the differences in GPU chip.

Uses of modifying a device’s clock speed

On one hand, controlling clock speeds allows a user to make the device run a device over its design limits (overclocking) in order to obtain a higher performance score. However, doing this could raise its temperature beyond acceptable levels and reset your device. Even worse, doing this could render your device useless.

On the other hand, if you use your Android device only for making calls, texting and social networking, then you can increase your battery life by reducing the clock frequency of the smartphone/tablet CPU using the free tool. The device CPU will run slower and offer less performance. Nevertheless,  these activities don’t require much CPU power, so you won’t notice any difference except for a longer battery life (and a cooler device).


Using this free tool, I was able to lower the stick’s CPU speed, making it run cooler and that, in turn made it much more stable with virtually no resets, at the (rather unnoticeable) expense of a lower performance score. But, since I don’t use the device for gaming or any other heavy, CPU-intensive applications, I can’t complain about the change.

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