Advanced Micro Devices Inc (AMD)

[XP40000]

We have to be realistic about 64 bit.
It is not Viagra and it is not free.


At archirecture level, x64 gives 64-bit addressing and a few more registers. Existing PC software can't take advantage.
This is unlikely to change any time soon.

At micro-architecture level, let's assume that Barton and Hammer are very similar.

The killer is at logic/circuit level. In 64-bit design, there will be several places on the data path that needs 64-bit adder, instead of 32-bit adder. Consequently, for the same micro-architecture, 64-bit design will be at least 20-30% slower in terms of MHz.

Unless the application needs 64-bit addressing, you give up significant performance for nothing.


AMD must address the mainstream market: the PC market where 64-bit addressing is not needed at least for another 2-3 years.


Attach the Hammer interface to the Barton core will let AMD lead PC performance for at least 1 year.

Longer term, x64 can migrate to PC and AMD can win. Near term,
AMD has a big hole on the roadmap in 2004-2005.