AutoCAD Processor

Core i5 430M then Core i3 350M and T4400.

Autocad is not thread optimized as some of the other apps like 3DS Max.. So the fastest processor of the lot (based on clock speed) will be more better in handling it at the present.. But future iterations and may be patch updates will change this scenario.. All in all, safest to go with the i5..

^ Well said! +1. Anyways, I'd go with the i5 or i7 if possible due to the availability of Turbo Boost for those CPUs.