Quick questions about overclocking C2D vs. X2

[nullpointerus]

Prime95 used to just quit with an error on my X2 rig when my overclock turned out to be unstable. That hasn't happened on my C2D; I just get BSOD's when the voltage is just a little too low for the clock speed. Is this normal for a C2D chip, or have I hit some other limitation in the system?

 

[SerpentRoyal]

Normal.