Overclocking Non-K series i5-2500, Which method? And problems.

Alright, so I will get right to it. First my problem is I am able to change my cpu multiplier too x41 thus clocking my cpu at 4.1 Ghz, Windows reports it at 4 Ghz, good. Now when running CPUZ with Prime95 it reports my processor running at x38, 3.8 Ghz at a Vcore of 1.054 and that is as high as it goes. All I did was raise the multiplier and turn Turbo Boost OFF and my Vcore is set to AUTO. Now is that what is causing my problem? is my Vcore too low? And if I raise my Vcore will it not ruin my C5/C6 state for downclocking upon idle?

This bring me to my next question. Is it better to just leave the cpu multiplier alone and turn Turbo Boost on and just raise the Turbo Boost core multiplier's? Or is my method good except im missing something? All suggestions are appreciated.