Ok so today i just put in my new heatsink so that i can overclock, before i was getting temps of 55 C and now i put my new one it it is only down to 49C i am using speedfan could it be giving me inacurate readings. I have and E8400 and it is said to run at 3.0 when i load CPU-Z it flickers between 2000 MHZ and 3000 MGZ what is that, and lastly it says my memory is running at 400 Mgz when it is 800Mgz DDR2. Is there a better temp. program that may give me better readings.

Did you apply thermal paste? what kind and how much?

What cooler did you use?

Yes your motherboard throttles down your CPU when not in use. When you need 3Ghz your motherboard adjusts to deliver that.

DDR2 stands for Double Data Rate. If it is running at 400Mhz that means it's doubled = 800Mhz.

ok i used artic silver 5 and put grain size in the middle and spread it evenly with my finger in a plastic bag, but before with stock i was getting 55 and that just seems way too hi especially my case has great vent.

my cooler is, Zerotherm Zen F120

You don't need to spread around your TIM.

Follow these directions from Arctic Silver:
http://www.arcticsilver.com/pdf/ap [...] l_wcap.pdf

AS5 has a break in period. It will get cooler after after a few days.

You should use RealTemp to measure your core temps.

If your cores are running over 40C at idle according to Realtemp, even with fresh AS5, you have a problem.