In fact, I've built my own independantly controlled air cooling system. The CPU is being cooled by a quiet 120mm fan and a modified 80mm fan to cool the upper part of the heatsink.
Temperatures °C (idle/load): On-board CPU sensor: 44/47 Manually installed sensor: 47/49,5
Ambient temperature is about 24°C. My own sensor is in between the 2 cores and is secured to the heatsink.