Core speed jumps under full load ?

[gherr74]

hi every 1 , i just built a new set-up. cannot get this thing to o`c ... i tried im new to oc. i dont no what to keep on auto / disable / enable , voltage ect ect... my 1si try i did 4.5 GHz booted and evrything was working fine. opened up cpuid / intel burn test. started test voltage was good , but cpu idles at 1600 - then when i put load hits the 4.5 ghz for a few sec`s then drops down to factory 3.5 ghz . i dont wanna fry nothing so thats why im here..i need a guide / tuturial / video to let me know what i should keep on auto / disable / enable / voltage...plzz help guys with anything.. thank you plzzzzz help me

heres the specs

i7-2700k cpu / with Contac 30 CPU Cooler 120mm fan = works very well

asrock Z77 pro 4 - m motherboard / all bios and up to date.

corsair Vengeance Series memory modules, 8GB (2x4GB) 1866MHz

Kingwin
MKX-850W 850 Watt PSU

Seagate - Barracuda 1TB HDD

EVGA GeForce GTX 590 (Fermi) Classified 3072MB 768-bit GDDR5 video card

Rosewill GEAR X3 Gaming Tower - 1 . 140mm / 5 - 120mm fans

 

[nna2]

how hot is it getting, if it's hitting TJunction that would explain the drop

 

[gherr74]

its not running hot at all about 30c idle 55c full load

 

[mkking.791]

i put mime at 1.385 volts for the vcore and mine is stable enough i just cant run prime95 and mine is oc to 4.5ghz and gets spike up to 7.2ghz. if you have a good mobo like i do i have a gigabyte p67a ud7 b3 and it will error if i mess up on the oc so it won't fry stuff on purpose unless you turn off one setting which i never do. and find out how to set your v droop properly as i said mine is a i7 2700k it's lows some days are 500mhz and the top end around 6ghz spike but mainly idle at 1.6ghz or 4.5ghz and never gets over 65c low of 22c at least that what hw monitor tells me.