Click here for the i7 980x How-to

Click here for the i7 2600K How-to

“CPU lapping is the sanding of the headspreader (HS) to remove imperfections

and to try and get the HS to be as flat as possible

so that there is optimal contact with your cooler.”

Intel i7 940

4-6 °C difference

Intel i7 950

3-5 °C difference

Intel i7 980x

5-10 °C difference

Intel i7 2600K

Difference .. No idea..