Ok so i have an Evga X58 Classified 3-way sli motherboard and i am debating to get an i7-920 or the i7-940. I am looking to overclock to 4+ GHz. I have a water cooling setup. Can anyone point me to a guide or what i can overclock max to?
You don't need an 940 to reach 4Ghz. The 920 is much cheaper and performs very well. Anyway, If I were you I would buy the 930 (the replacement for the 920).
The way I look at it is the 940's are going to be C0 stepping and the 930's will be D0 stepping while the 920 will most likely be a D0 it is not a sure thing. For the guaranty of a D0 I would go for the 930 even tho a 920 is pretty safe right now also.
If the cost is not in concern, 940 will be the best AT STOCK. However, they should have very similar OC potential and therefore don't expect to see significant advantage of 940 over the rest two.
The max OC for all of the 3 models will be very similar and 930 will be your best choice considering it has one more multiplier than 920 with merely $8 more.