Intel follows AMD lead on 64-bit x86 architecture12 Apr, 2004
Research by In-Stat/MDR's Microprocessor Report indicates that the 64-bit x86 architectures from AMD and Intel are almost, but not quite identical, so that in some cases programs written for one 64-bit architecture may not run properly on the other. The 64-bit x86 processors also support legacy 32-bit applications.
Microprocessor Report compared instructions, memory-addressing schemes, registers, and other features and concluded that Intel had patterned its 64-bit x86 architecture after AMD64. "Intel's reverse-engineering of AMD64 marks a major turning point in the historical relationship between the companies," says Tom R. Halfhill, a senior editor with Microprocessor Report. "This is the first time AMD has truly steered the direction of the world's most important microprocessor architecture."
The few differences that Microprocessor Report did find may be resolved in future 64-bit x86 processors or, in some cases, can be accommodated by adjustments in software code.
"We found nothing to contradict Intel's promise that its 64-bit x86 processors will run the 64-bit operating systems developed for AMD64," says Tom R. Halfhill, a senior editor with In-Stat/MDR's Microprocessor Report. "At the same time, Intel's reluctance to make a blanket guarantee about mutual 64-bit software compatibility is justified by the minor differences we discovered."