Slow CPU?

[wildwood]

Is it possible to only partially cook a CPU?

I always though that a CPU either goes or not, no inbetween. The last few weeks my comp has slowed down to the point that even opening IE takes 6 or 7 seconds and frequently the comp restarts itself. Checked programs running and even reinstalled Windows. Tried another graphics card but no change.
When I ran SpeedFan the cpu temp was over 70°C. but the speed was at 46%. Probable reason for restarting. It seems that the mobo fan adjustment does not work so have installed another fan over cpu that runs of a molex plug so runs at 100% all the time keeping the temp healthy. The processing speed however is still very slow and nowhere near the original.