Friday, June 03, 2005

Windows x64 home truths...

Nathan Mercer (Microsoft NZ) has been running around New Zealand, touting Windows x64 with AMD and has put some interesting tit-bits in his blog.

I was reading this article from Microsoft and noticed a few things:

  • Windows x64 does not use 64bit memory addressing, it uses 40bit! (OK, that's still 16 terabytes of addressable memory.. but still, a little misleading)
  • WinXP Pro x64 has a physical RAM limitation of 128Gig, while Windows Server 2003 Standard Edition has a limit of 32Gig!
  • One of the reasons for increased performance is the increased number (and size) of CPU registers.  Hmmm.. but we see this often with CPU revisions within x86 (SSE/SSE2 [and SSE3?] added new, longer registers).  But by and large, the main reason for performance is the increase in physical RAM, if you have it installed...
  • Security is improved. Data Execution Prevention (DEP) in this case.  Two points here:
    1. MS implemented limited DEP in software, even when you don't have a DEP capable CPU
    2. There was no reason that DEP support couldn't have been put into x86 CPUs, INTEL/AMD just need to give you a reason to upgrade...
  • Compatibility.... Hmm... if we don't use Windows x64, there's no compatibility issue...  If we do use Windows x64 aren't we glad that it's "... essentially feature comparable with the 32-bit versions."  Hmmm... that's "comparable", not "compatible".  I guess MS is starting to learn some lessons from Windows on Alpha and Windows on Itanium (OK, so the underlying CPU's weren't x86 compatible either, but they're doing it for Xbox 360...).  BTW no 16bit support at all!  No support for 32-bit drivers (better hope your printer/scanner/modem/webcam/etc vendor has released a new driver...) or applications that depend on 32-bit drivers (except MS Exchange, funnily enough...)
In summary, I'm sure this will all be moot point in a year or two, since you'll only be able to buy machines with x64 based CPUs and hardware vendors will have released drivers and no-one will notice the difference in performance, cause MS Office will be bigger and slower, Windows will have even more bells and whistles (Longhorn?) and for 90% of corporate users, a P4 2.0Ghz, with 512MB RAM, will still be more than enough to run WinXPpro with Office2003...
[I must be grumpy today, too much ranting, better do some work... yeah, like that's going to cheer me up!]

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