Which temperature reading should i go by?

I wasnt sure were to post this question, but i wanted to know which cpu temperture reading should i go by the main cpu temp or should i go by the temps for the seperate cores ?

yes for overclocking.

I prefer to use the core temps, but the reading output is more sensitive, thus more irradic than the CPU temp. With overclocking, you will probably be pushing the maximum more often, and the core temp would be quicker about detecting any problems.

EDIT: If you use automatic controls to alert or shutdown with a high temp, the core temp is more likely to trip this due to spikes, so I would rely on manual monitoring.

thank you for you help.

That wouldn't be a bad idea, but it would seem to me that the CPU temp would be effected by the combined temperature of both cores. For instance, if one core was idle, and the other maxed out, wouldn't the CPU temp display a mean temperature of probably 50% of the core's maximum? If so, that wouldn't protect against an overtemp on the active core..