> Well, nearly. Itanium Merced was 2001 [1] (althoug you wouldn't buy
> /that/ as a private person), DEC Alpha was even 1992 [2];
FWIW And MIPS was there even a bit earlier with their R4000 (tho the
software support for it only appeared some years later: they first
wanted to have an installed base to which to deploy the software), which
I believe was the first 64bit microprocessor.
And the demise of the DEC Alpha was quite unfortunate. It was super-fast and OSF/1 was rock-solid. But DEC lost the competitive bid on that project and Sequent/Dynix, based on hundreds of 486 CPUs, won it. Now owned by IBM and deep-sixed: They really bought the customer base instead.
The final pedantry is that, contrary to an earlier post, the first IBM PCs were built around the 8088, not the 8086.
IIRC the claim back then was that adding 64bit support to the R4000 was
rather cheap (it increased the die area by a few percents only, and
64bit adds were still fast enough not to slow down the overall chip's
frequency).
The same must have been true for the Opterons (except that the increase
in die area much have been even much smaller since the CPU itself had
become a much smaller part of the overall die because of the
incorporation of things like the memory controller and the L1 and L2
caches).
So it was a great move on the part of AMD: cheap to implement but with
an enormous marketing impact.
Stefan