Skycop
I read somewhere not to long ago, that the big boys produce all cpus equal (cheaper on production line costs) and mark the processors according to market demand. The big boys like to make loads of dosh on the higher rated units but also like to keep thier finger in the pie of the lower end of the market. Running two production lines would inccur more expense which would eat into profits.
You are quite right about the possibility of frying the processor, small steps are recommended when upping the frequency and voltages (especially voltages) of the cpu.
I use an Abit BE6 motherboard (built with the overclocker in mind) which monitors the temp of the cpu via a small thermistor inserted close the processor and its heatsink, very useful little gadget.
Have you overclocked your machine