I believe that the mini 10's use an atom processor, which really shouldn't get that hot. Do you know what kind of temperatures it is putting out? I ask because if a fan or something has broken down, the chip could be overheating, which will lead to the chip to throttle back performance in order to stay within it's normal operating temperatures.
If you do not know the temps, google a program called "Speedfan" and install it (it's free) or if that doesn't work, try something called "RealTemp." From there run either and tell us what kind of temperatures you are getting.