The x86-64 instruction set extension of the x86 ISA to 64 bits is fundamentally no different or more difficult than Intel’s extension of the original 16-bit x86 architecture to 32 bits, starting with the 80386. The addition of 64-bit capabilities to the K8 processor will likely offer little benefit to the vast majority of AMD’s existing K7 customers who predominantly use it to power desktop computers for the home market. Although AMD has clearly stated its intentions to compete in the technical workstation and high-end server market with K8, the lackluster chipset support to date for the mainstream K7 processor family calls that into question. Chipsets for large scale multiprocessor systems are far more difficult to design, implement, and verify than uniprocessor chipsets for PCs. A bigger challenge than chipsets is that buyer’s conservatism increases with the size and cost of the hardware. AMD will likely find the large scale server systems an even tougher nut to crack than the business desktop PC market.
On the upside the move to 64 bits will have negligible negative impact on the performance, manufacturability or cost of the K8, a high end MPU implemented with tens of millions of transistors. And x86-64 will offer an upgrade path to those rare x86 users who need 64-bit flat addressing. The K8 can offer that, but without the performance loss on legacy applications inherent to IA-64’s x86 compatibility mode. For most users, the K8’s TFP RISC-like FP extension may be of much more interest since it should provide eventual benefit for users of high performance 3D graphics applications, such as games. What K8’s 64-bitness and TFP provides to AMD is the means for it to counteract the huge advertising campaign that will accompany Intel’s push to move its customer base from X86 to IA-64, which will likely start in earnest in about two or three years. Finally, the recent intriguing patent disclosure by AMD also suggests that we cannot discount the possibility of a big surprise when K8 is introduced.
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