Actually AMD defined the 64 bit extensions to the 32 bit x86 architecture, and Intel had to follow and is letting the Itanic sink.
Of course Intel does not even remotely admit it (and even Linus ranted on this fact in a mail a decade or so ago), but they have still not come over the NIH syndrome that it caused them.
That was the brief window that AMD had the upper hand. On the processor architecture side, Intel was splitting resources between hoping non-backward compatible Itanium was the future, and the disaster known as Netburst in the Pentium 4. Netburst had terrible performance, too high power consumption, but they were able to claim higher Ghz. All Intel had was name recognition, but technologically AMD was leading with the K7 and K8, and on this they were able to launch 64 bit. Even though it'd be the better part of 6 years before 64 bit really caught on, it was backwards compatible so it didn't cost anything to have but not use.
Intel only got ahead when a small group in Israel threw the Pentium 4 in the garbage, and started back at the Pentium III to design the Pentium M as an efficient mobile processor (which ushered in the confusing line of Centrino mobile platforms, that had Pentium M, Intel chipset, and Intel Wifi, not an actual Centrino processor). Intel eventually threw the Pentium 4 wholesale in the garbage, and expanded on Pentium M to form Core/ Core 2, and then from there i3/5/7 family. The rest is history.
I like to root for AMD as the underdog. When I bought my laptop 8 years ago, though perhaps not as good on battery, my AMD was best bang for the buck, and the low end graphics it had blew away Intel's junk i945. Sadly last year when I went to spec a new desktop, I wanted to want AMD, but Intel simply blew it away with performance. On normal desktop functions I feel single thread performance plays a major part in the CPU bottle neck. With a quad core, additional execution units are going to give marginal incremental improvements if you're not running a highly parallel workload. My i5-4690 stood out as the obvious choice.
AMD was riding high when Intel made a major mis-step with Pentium 4, but those days are long behind them, and they seem to be circling the drain. Spinning off, outsourcing, always behind on Fab technology, and a fraction of the R&D budget of Intel it's hard to compete.