Cooling is a challenge in all small and slim PCs and as you already had a chance to see, the size of the heatsink and fan is limited by the size of the chassis.
As the graphics core is integrated in the CPU, the whole cooling system consists of a single heatpipe with a heatsink and fan. The HD4 needs to be mounted upright to provide the best possible airflow. Now for some good news. We are happy to report that the HD4 is quieter than the HD3. It is still possible to hear the fan under load, but it really did not bother us much, although it is still audible in complete silence, at night.
It’s not possible to adjust the fan speed in bios. At default settings the CPU temperature is 38°C in idle, but under load it can hit 66°C, while the graphics part goes up to 70°C. These results are pretty good, especially when compared to the HD3.
The Celeron 847 is a frugal low voltage processor is designed with mobile gear in mind, so it has a TDP of just 17W. Power consumption is pretty low as according to our measurements the HD4 consumed 15W in idle and up to 34W under full load. This is a few watts more than the HD3, but all in all the results are very impressive, since it offers more performance as well.