Intel has yet to release its next-generation micro architecture next month, but apparently folks in Taiwan have already managed to obtain and overclock an engineering sample for a Nehalem-based Core i7 965 Extreme processor - with some very promising results.
According to CPU-Z screenshots, the Core i7 chip made it from its 3.2GHz stock speed all the way up to 4.2GHz using a core voltage of 1.72V - which is above the danger-mark if we take Intel's warnings into account. By the same token, overclockers at the Coolaler forums have done the same with an unreleased 45nm AMD Phenom, reaching the 4GHz mark but with a somewhat tamer bump in voltage to 1.6V.