**2. Experimental Measurements**

Measurements have been carried out on a Samsung RC dual core, including AMD E-350 (AMD, USA). This chip contains a dual core GPU Radeon 6320/6310 C (ATI Technologies, Markham, ON, Canada). Figure 1 shows the activity (or CPU usage) and the temperature of the CPU versus time. The temperature of the GPU is also displayed. The GPU is a di fferent integrated circuit. The chip contains a dual core CPU (2x Bobcat) with a L2 Cache (L2 Cache—it is a level of memory, general meaning), a GPU with DirectX v11 GFX (Microsoft), and RAM DDR3 (standard); its temperature will not be used further on in our analysis. Nevertheless, it is clear that both temperatures have a similar, almost identical behaviour. Note that all the temperatures are temperature rises above ambient temperature, i.e., of the metal base plate connected to the cooling fin through a heat pipe.

**Figure 1.** Microprocessor activity and CPU/GPU temperature.

Special software has been installed to measure the activity of the CPU. Activity is measured on a relative scale from 0 to 100. Figure 1 clearly demonstrates the correlation between the activity and the CPU temperature. During the first 21.6 min (=arrow shown in Figure 1), the activity varies around the value of 20. After that period, the activity was increased by a factor 4.5 up to a value around 90. Nevertheless, the temperature rises from 59◦ to 88◦ (=59◦ + 29◦) (after extrapolation to steady state). Hence, the temperature is not proportional to the activity. This is due to the technology used for the processor. The power dissipation (and hence the temperature rise) consists of two components: a constant value and a variable component proportional to the clock frequency or, in other words, the activity.
