[adrian_b]

Core 2 as an individual core was significantly better than AMD's competing core (e.g. by being able to issue 4 simultaneous instructions vs. 3 instructions for AMD).

Nevertheless, the integration of multiple cores into an Intel multiprocessor was very inefficient before Nehalem (i.e. the cores were competing for a shared bus, which prevented them from ever reaching their maximum aggregate throughput, unlike in the AMD multiprocessors, which had inherited the DEC Alpha structure, with separate memory links and peripheral interfaces and with an interconnection network between cores, like all CPUs use now).

However this was noticeable at that time mostly in the server CPUs and much less in the consumer CPUs, as there were few multithreaded applications.

Core 2 still lagged behind AMD's cores for various less mainstream applications, like computations with big integers.

Only 2 generations later, after Core 2 and Penryn, with Nehalem (the first SKU at the end of 2008, but the important SKUs in 2009) Intel has become able to either match or exceed AMD's cores in all applications.