get a water cooling solution.....or not a better heatsink and fan like zalman or cooler master....
I have a Sempron 2800+ at 2.0Ghz on stock HS and fan. I overclocked it to 2.2Ghz still with stock HS and fan. I did a CPU burn in max temp. is at 50 Celcius...I have 2 80mm fans at the back and 2 80mm fans in front for better airflow...Voltage is at 1.68v yes its not constant it keeps on changing...
I think the cpu needs better cooling considering the higher voltage it is taking....it just generates more heat...