We know this story.  Intel got in it’s tick-tock groove with alternating process/architecture generations of CPUs.  AMD managed to get stuck in a low performance rut.

When I built my current PC, an Intel Core i7-920 Nehalem based system, it was a significant upgrade from the AMD Athlon XP based system I had before.  On a single threaded workload, it was almost three times faster.  With a multi-threaded workload it was 13 times faster.