I would ask what type cooling fan are you using on the APU. I know that I have an after market Cooler Master fan. The stock fan caused high temp with my A10-5800K.
If you have access to thermal paste I would clean and reapply the thermal paste. Not hard to do just need some rubbing alcohol, coffee filters and thermal paste. Use the coffee filter (non static cloth) with rubbing alcohol to remove old paste. Be sure to clean the top surface of APU and the bottom portion of the cooler. Allow to air dry and then apply a pea size drop of thermal paste to the middle of the APU surface. Place your cooler fan back in place. It will take a few days for the paste to cure.
If after that you still having high temps get online and get an after market cooler.
AMD A10-5800K, XFX 7850 Ultra OC Edition 975MHz, 16GB RAM, Win 8.1 Pro 64 bit, MSI 7778 motherboard, 500W PSU, HP P7-1235, CCC 13.12 WHQL