"When Intel pushed the Core i7 out the door it was not to top its rival, AMD, but to top its own Core 2 CPUs. We saw the i7 simply trounce on just about all other single socket systems (and some multi-socket systems as well).

Intel did not sit back and relax, though; they took the C0 stepping and tweaked it to give it an extra edge. Soon everyone was talking about the D0 stepping of the i7; it had better headroom, better thermal tolerance and even seemed slightly faster than the same clocked C0 CPU."