Try and confirm that your temperature sensors are functioning correctly; those temps seem way too good, especially for a chip with 1.7v applied to it. Try coretemp or realtemp as well, but I think HWMonitor would be displaying it correctly. Also, put a thermometer in your room and make sure your CPU doesn't idle below the temperature of your room or something like that. It could be that you got really lucky and got an awesome chip for overclocking but something just seems a little off. You might want to try dropping the voltage a little and see if it's still stable. I don't really have any OC experience though so you might want to wait for someone else to chime in before you change anything.