Accuracy between mobo thermistor and the V9 thermal probe?

Hi guys

I've been thinking around this for a while... I use hmonitor to monitor all temperatures on my system. Currently I get 47C idle and 55C full load.

I use a V9 as a cooler with that automatic option enabled, with a layer of Artic Silver 3. The manual says the V9 will reach its maximum fan speed (4800 rpm) only if the processor reaches 55C.

I noticed the V9 is not going to 4800 rpm while the cpu temperature is reported at 55C. Instead, it runs at 4000 rpm. It will only go up to 4800 rpm if the processor hits 60C. Right now, it's reporting 47C and 3400 rpm for the V9. So, could it be possible the board has a +5C variance on real cpu temperature?

I asked Thermaltake about this issue, here's their answer:

IT is normal in your situation due to mainboard has to go through softwares and could range from 5 degrees difference compare to our thermal probe.

Click to expand...

So, which reading is more accurate? The board thermistor or the V9 thermal probe?