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64bit CPU/OEM Questions??

By Cucumber Ā· 8 replies
Apr 18, 2002
  1. At the end of the year i intend on upgrading to an AMD Clawhammer, and getting Windows XP 64bit version. And i want to know, if i got 64bit Windows would i still be able to run 32bit applications??
    And does anyone know if the 32bit performance of the Clawhammers will be better than current performance(Athlons)??

    Any help would be great, thanks

  2. Phantasm66

    Phantasm66 TS Rookie Posts: 5,734   +7

    Of course a 64 bit processor can still run 32 bit applications.... Your 32 Bit processor can run 16 bit processes, can't it??? And it would be silly if Windows 64 bit couldn't run 32 bit code.... I should think there would be some kind of outcry if you have to rebuy Office in 64bit version just to run it on your new rig!

    You don't even HAVE to run a 64bit version of Windows or Linux, you can run the 32bit.... It just runs it as a 32 bit process....

    Its just that the 64 bit versions of these Operating Systems will be better optimised for these processors... And, of course, you can't run the 64bit versions on a 32bit processor.... But I am guessing you already figured that...

    I imagine that there will be some compatibility issues, but not that many....

    Oh, and I was reading somewhere that Mac OS X was being ported to the 64bit athlon as well.... so maybe you can run that alongside windows and linux as well...
  3. Phantasm66

    Phantasm66 TS Rookie Posts: 5,734   +7

    Microsoft's web site mainly talks about the Itanium processor by Intel as being the processor of choice for the Windows XP 64 bit edition.....

    ....I imagine that it will also support the 64 bit Athlon processor as well.... But I have no firm evidence to support this.... Surely, though....

    Some interesting facts:

    64 bit 32 bit
    Virtual memory 16 terabytes 4 GB
    Paging file 512 terabytes 16 terabytes
    Hyperspace 8 GB 4 MB
    Paged pool 128 GB 470 MB
    Non-paged pool 128 GB 256 MB
    System cache 1 terabyte 1 GB

  4. Mictlantecuhtli

    Mictlantecuhtli TS Evangelist Posts: 4,345   +11

    Silly, perharps, but I wouldn't be surprised if they'd do that.

    But note that 64-bit code takes twice the space & bandwidth when compared to 32-bit code. I'd say that affects speed.
  5. Phantasm66

    Phantasm66 TS Rookie Posts: 5,734   +7

    Oh, I've found out of few things whilst researching your question:

    *It appears that Windows 9x operating systems like Windows 95, 98, ME, etc will not run on the Itanium. Maybe Clawhammer too....

    *The Itanium will not run 16 bit code and DOS apps any more....

    *Microsoft so far is only promising to create a 64 Bit windows that runs on the Itanium, not the 64Bit AMD processor!

    *The 64Bit AMD processor will run Windows 32 bit versions just fine.

    *Linux will support the AMD 64 bit processor....


  6. SNGX1275

    SNGX1275 TS Forces Special Posts: 10,729   +409

    Now wouldn't that be something if Apple would decide to let their OS run on 64Bit Athlons while Microsoft wouldn't allow XP to run on Athlons....
  7. erwin1978

    erwin1978 TS Maniac Posts: 290

    If my memory serves me right, the Itanium cpu is purely 64 bit with a completely new architecture. 32 bit applications can be run on a 64 bit OS through software emulation only.

    The Hammer will be a 64 bit processor that augments the x86 architecture. 32 bit applications will be fully compatible with this cpu since it's based on the x86 architecture; no emulation is needed.

    In terms of noticeable increase in performance when running a 32bit application on a 64 bit cpu, I doubt it.
  8. Didou

    Didou Bowtie extraordinair! Posts: 4,274

    The Hammer line of CPUs will definitly see an improvement over the Athlon CPUS even when running 32bit applications ( even at equal speeds ). When software will be optimised for 64bit, the increaase will be even more noticeable.
  9. Rick

    Rick TechSpot Staff Posts: 4,572   +65

    Phantasm: I've read from a number of sources (including The RegisterĀ®) that Microsoft has been working closely with AMD to optimize XP64 for their Hammer processors. I've even heard of apparent favortism for AMD over Intel from MS.

    Anyone here with an Itanium? I'm curious about this too, but I remember the Itanium being able to run 32-bit applications, although not necessarily natively. Rather than containing bulky legacy microcode, it has some sort of 32-to-64 translation mode. This converts 32-bit instructions to native 64-bit instructions so it can perform legacy operations too... But this type of hardware translation probably comes as a huge loss to CPU power.

    The Hammer will contain both 64-bit and legacy as one huge happy family I believe, by simply extending its intstruction set. But, I imagine this will take up some major die real-estate. It will likely result in lower 64-bit performance clock for clock, but I'm sure it will run both modern and legacy apps very fast either way. It's kind of a happy medium I suppose...

    I believe the reason Intel didn't just extend their instruction set to support 64-bit (Kind of like what they did to the 386 to support 16/32bit) is the following drawbacks: Die size. The larger the die, the more expensive, hot and slow the processor is. This streamlining really offers the best 64-bit performance I would imagine. But I really think we need to bridge the 32/64bit gap. We can't just jump into the 64-bit sea without at least something to float on.
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