First of all, what PSU do you have?
Guides should be used for reference, not strictly adhered to. Overclocking is never an exact science and your overclock will always differ from someone else's, even if the hardware is exactly the same.
If the VCORE is set to auto, then the VRMs will always allocate more voltage to the CPU than it actually needs.
My advice is to disable the overclock, do some more research, gain a greater understanding of what you're doing and then revisit it. This is a good starting point; http://www.tomshardware.co.uk/forum/272214-29-wolfram-beginner-guide-overclocking.
The Prime95 blend test doesn't push the CPU to its limit but rather simulates a typical load. The small FFTs test is what pushes the CPU threads...