Overclocking Blue Screen at Low Multiplier

[liquidbytes]

I have a intel i7-4770k cpu and asus z87-pro motherboard. For a while I have been running the cpu at stock speeds to make sure everything was stable. I recently decided to start overclocking it. I have never overclocked before so looks up some guides online. To start off I set my multiplier on all cores to 46 and set the voltage to 1.2V. Restarted computer and blue screen. I kept lowering the multiplier until I could boot Windows. I got to 42x, ran a stress test (prime95) for a while and the cpu seemed stable. After running prime95 for about 1 hour my temperatures get to about 65-70C. I am completely fine with this temperature. I would like to get a higher overclock but every time I increase the multiplier I blue screen. Is there something I could be missing? Should I reset my cpu? Re-apply thermal paste?

I have no idea why I can not get a higher overclock if my cpu temps are normal.

 

[computer_nugget2]

try undervolting.

 

[liquidbytes]

try undervolting.

to what?

 

[computer_nugget2]

undervolt a little bit and see if you can go lower with the multiplier.

whats the smallest increment the mobo lets you change the voltage?

 

[liquidbytes]

undervolt a little bit and see if you can go lower with the multiplier.

whats the smallest increment the mobo lets you change the voltage?

0.009 Volts. What will undervolting do?