AMD's is backwards compatible with x86 while Intel's is not. Given AMD's recent success, Intel's loss of credit, and the ease of shifting to a new architecture that supports the old architecture as well.
eau contraire(tm)! (Its not that simple.)
For the last six years Intel and HP have been developing a new RISC-like architecture called IA-64 that includes a compatibility mode that allows it to also run x86 code. AMD is taking the bold and controversial step of extending the x86 architecture (once again!) into full '64-bit hood' while retaining the ability to freely run x86 legacy code.
realworldtech.com
But, you make a point, because native 32-bit (x86) instruction support is different from 32-bit "mode".
Intel long ago decided against extending x86 to 64 bits and instead, in conjunction with Hewlett Packard, developed a completely new, RISC-like 64-bit ISA, called IA-64. Although IA-64 has an x86 compatibility mode it will very likely operate at a much lower performance level than native 64-bit code. Also, with IA-64 it is very difficult and inefficient to mix x86 and IA-64 code within a single application thread. It certainly seems that Intel intends to wean its customers off the x86 platform in favour of IA-64 starting first at the high end (servers and workstations). This contrasts sharply with the AMD's evolutionary approach which can support 32 and 64 bit x86 code nearly equally and apparently allow efficient mixing of code at the same level as can be done with 16 and 32 bit x86 code since the Intel 386.
realworldtech.com
Could it be that AMD will have MSFT in its value chain, and that MSFT will actually need AMD in its value chain?
If AMD succeeds in eliciting support for x86-64 from Microsoft then it will be quite obvious that it has taken over leadership of the x86 architecture. This is likely for several reasons. The biggest reason Microsoft would want to strongly support x86-64 is Compaq's recent public announcement that it would not support development of a 64 bit version of Windows as a product offering for Alpha. Microsoft has great ambitions for Windows challenging the traditional proprietary versions of Unix for the role of running the largest and most prestigious computer systems, the high end, multiple processor Enterprise class server. But these systems are almost exclusively based on 64 bit RISC processors.
With support for both IA-64 and Alpha, Microsoft seemed to have the two most powerful 64-bit platforms in its stable. The loss of Alpha makes 64 bit Windows an operating system exclusively targeted for IA-64. This leaves Microsoft's ambitions increasingly vulnerable to Intel, which has plans of its own. Intel is in the driver's seat for IA-64 because it can point customers to Monterey, Solaris, HP-UX, AIX and Linux as alternatives to Microsoft's 64 bit OS offering. As testimony has shown in the DOJ antitrust trial against Microsoft, there is very little love lost between these two ruthless and highly competitive giants.
(same URL)
But a serious word of caution:
There is no doubt about it, AMD is taking on a risky and ambitious course of action extending the ancient x86 architecture once more, this time to 64 bits. Even if they can deliver the new x86-64 instruction set in future products without impact to schedule or performance their destiny is in someone else's hands, namely Bill Gates. If Microsoft refuses to support x86-64 with tools, applications, and operating systems then x86-64 will simply fail.
In today's computing world, however, a 64 bit version of x86 might just be the magic bullet that Microsoft needs to offset Intel's growing influence and rebalance the power relationship in the Wintel oligarchy. It potentially provides another platform to support a 64-bit version of Windows. It also represents an insurance policy in case Intel has bet on the wrong technological horse in the way it designed IA-64.
Listen to the power of INTC's IPR for 64-bit architecture (as opposed for its loss of that BTE in the 16- & 32-bit architectures):
From AMD's point of view they had no choice but to develop x86-64 if they wanted to play in the high-end server and workstation marketplace. Any attempt to clone IA-64 would land AMD in the middle of a legal minefield stretching as far as the eye can see in all directions. The only other alternative would be to develop an analog to the IA-64. That is, a split personality MPU that supports both the 32-bit x86 ISA and a 64-bit RISC ISA. It is likely that Compaq would have licensed the Alpha ISA to AMD for use in a hypothetical bilingual processor if asked. But this approach is both more complicated than simply building a 64 bit x86 extension and would likely run afoul of Intel patents related to dual instruction set capability in IA-64.
Conclusion:
With its x86-64 extension solving the 64 bit addressing issue, AMD should be able to ride the x86 market for at least another 4 or 5 years. Since Intel is unlikely to respond with a 64-bit x86 design of its own (and risk sabotaging market acceptance of IA-64) it seems that AMD is destined to take over the x86 leadership role.
tolachi, thanks for that very informative URL. It's worth a read by all INTC investors with just a little bit of CPU-tech savvy. |
