I am going to attempt to mod my ssdt with this tutorialhttp://macmanx86.blo...ml#comment-form
I edited this post because it was too long and a different motherboard/processor but in general this is what I have observed about the error 18 and kernel panic.
P-State Stepper Error 18 at step 2 in context 2 on CPU 1,2 etc.
I could be wrong but I think you have to have a minimum number of p-states in the ssdt. I had 14 and I kept getting that error until I edited the sections in the ssdt to exactly the specs of my processor , 22 steps from 800-2900, and 4 turbo states near the beginning of the ssdt script.
I think I kinda prooved the minimum number of pastes needed for a particular processor because when I inserted my two basic sections into a working ssdt such as one from Tonymac's MultiBe... I got the error 18 then kernel panic. With either 4 or 9 turbos stated, it did not matter, I still got the error when I inserted only 14 total pstates.
Name (APSN, 0x09) <<< Either 4 or my default 9 still gave me the error. All i7's in general should have 4 turbo's, check your specs.Name (APSS, Package (0x0E) <<< My default ssdt was 0E, 14 states. After I changed this to (0x16), and inserted all 22 states, I was able to boot.
I used tony's working ssdt for a while but his had 24 states ranging from 1600-3900. I just modified his to range from 800 to 2900 which is what the mobile processor i7-2630QM calls for.