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Intel Quietly Adopts AMD's x86-64

Posted by timothy on from the or-an-incredible-simulation dept.

HishamMuhammad writes "The rumors reported earlier at /. are confirmed. The latest offerings in the Pentium 4 family now support AMD's x86-64 architecture, even though Intel is not willing to admit it very openly, by using cryptic names like EM64T and (gasp) IA-32e. (The naming issue was discussed on lkml, and the consensus there was to use 'x86-64,' even though sometimes AMD refers to it as 'AMD64'). Intel's FAQ admits their implementation is basically compatible with x86-64, except for the minor differences that have always set Athlons and P4s apart. It's about time Intel jumped on AMD's bandwagon, since its homegrown 64-bit architecture seems not to be doing very well."

7 of 392 comments (clear)

  1. Sound fine and all... But.. by Folmer · · Score: 5, Interesting

    How will it perform compared to AMD's chips? AFAIK AMD usually performs better clock to clock?

    1. Re:Sound fine and all... But.. by captaineo · · Score: 5, Interesting

      I just got a 3.2GHz dual Xeon with EM64T. It runs the standard x86-64 Linux kernel just fine. Emulation of 32-bit software is excellent (the performance penalty is ~1%).

      In my (64-bit) rendering benchmarks, the 3.2GHz Xeon is just a tad slower than a 2.2GHz Opteron 248.

      On my benchmarks, Opteron performance benefits massively from switching to the 64-bit architecture (30-40% faster than the same software in 32-bit mode). But, on the Xeon there is virtually no difference. This leads me to believe that Intel's implementation of the 64-bit instruction set is far less optimized than AMD's. Or, perhaps GCC emits code that favors AMD's design over Intel's.

  2. Struggling Intel by mntgomery · · Score: 5, Interesting

    I suppose in most technical circles that always pull for the underdog and cheer when the big dog stumbles that items like this come as great news. But its appearing more and more like Intel is the one playing catch up. They may still have market share and a far wider range of products to support them, but AMD has taken the Intel bull by the horns and is beginning to bring it to its knees. Problem is, its the competition that has driven the market and without Intel, AMD has no identity. I just hope Intel can turn things around.

    --

    This comment was generated by a squadron of trained super elite albino ninja chickens for you.
  3. FYI by remigo · · Score: 5, Interesting

    As an interesting side note, check out this story. It says that Intel reverse engineered the AMD64 architecture (which isn't terribly surprising) but then flat-out copied the documentation, even though some of their implementation didn't match up!

    Nice one, guys.

  4. Intel chips miss a critical component: the IOMMU by Anonymous Coward · · Score: 5, Interesting

    The Intel chips don't have an IOMMU. This means that unless the chipset provides one (none currently do) 32 bit PCI cards cannot do DMA into memory beyond 4GB, forcing the use of bounce-buffers.

    In short, 32 bit PCI cards on systems with > 4GB memory will be G L A C I A L L Y S L O W.

    On AMD64 the IOMMU remaps memory for 32 bit DMA below 0x10000000, thereby allowing 32 bit cards to access the full 64 bit address space.

    The lesson: Buy the original. Buy AMD.

  5. Linus's view by pavon · · Score: 5, Interesting

    For those who missed it last time around, Linus was also tempted to call it amd64 in reaction to intel's handling of the subject but decided to stick with the vendor neutral x86-64.

    And yeah, this moved from the realm of rumor to fact nearly a year ago :)

  6. Re:Just as a side note by damasta30 · · Score: 5, Interesting

    I believe that AMD64 is the right way to go. Not just because I am an AMD guy, but because it is fair. AMD created the spec, and Intel copied it. Give credit where credit is due.