my dv6 cpu started running hot less then a year after I got it. they had used cheap thermal paste on the cpu and gpu. just changing that out lowered my nomal temps (and my lap felt it to ) by 20 degrees F. My heat sink didn't have any build up on it but if it does that can be part of the issues. You can also look up how to take apart your labtop to do it on youtube(takes some time and small screew drivers but its not hard). I spent an hour to do mine. my typical full load temp is 170F with 500mhz overclock. (hard core gaming).
My system is also the amd version. A8 with separate gpu. The same heat sink cools both the cpu and the gpu which is kinda bad and limiting overclocking.