One of my friends just told me that having intel speedstep enabled while overclocking the cpu can cause overvolting.
Is this true?
Speedstep somehow fixed a performance issue and it'd suck if that was true.
No, you need smarter friends.
Intel Speed Step changes both the clock multiplier and supply voltage on a per-core basis. Historically, execution was paused while both the clock multiplier and supply voltage were changed at the same time, but recent architectural revisions (Haswell?) have decoupled these adjustments such that the pause in execution is greatly reduced.