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A question about 32-bit apps running in 64-bit WIndows 7

Discussion in 'Windows 7' started by Al Dykes, Mar 18, 2010.

  1. Al Dykes

    Al Dykes Flightless Bird

    Does a 32-bit application run on a 64 bit machine use any sort of a
    compatibility layer, not that this is a horrible thing.

    Has anyone benchmarked the performance of a heavy application such as
    32-bit Photoshop under 32-bit and 64-bit Windows?

    (I dunno if there *is* a 64-bit build of Photoshop yet.)



    --
    Al Dykes
    News is something someone wants to suppress, everything else is advertising.
    - Lord Northcliffe, publisher of the Daily Mail
     
  2. LouB

    LouB Flightless Bird

    Al Dykes wrote:
    > Does a 32-bit application run on a 64 bit machine use any sort of a
    > compatibility layer, not that this is a horrible thing.
    >
    > Has anyone benchmarked the performance of a heavy application such as
    > 32-bit Photoshop under 32-bit and 64-bit Windows?
    >
    > (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >
    >
    >

    The main advantage of 64 bit is that it allows use of large amonts of
    memory easily. So if Photoshop likes to use a loy of memory 64 bit
    might help.
    Try Google for more info/ideas
     
  3. Al Dykes

    Al Dykes Flightless Bird

    In article <4BA21369.4000402@invalid.invalid>,
    LouB <Lou@invalid.invalid> wrote:
    >Al Dykes wrote:
    >> Does a 32-bit application run on a 64 bit machine use any sort of a
    >> compatibility layer, not that this is a horrible thing.
    >>
    >> Has anyone benchmarked the performance of a heavy application such as
    >> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>
    >> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>
    >>
    >>

    >The main advantage of 64 bit is that it allows use of large amonts of
    >memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >might help.



    I understand that and know that 32 bit apps are compiled into segments
    and the is overhear in inter-segment calls. From what I know of
    mainframe memory, the 64 bit flat memory model is a win for apps that
    are compiled for it.

    My question stands, is there any sore of compatibility layer between a
    32 bit app and 64-bit Windows?


    --
    Al Dykes
    News is something someone wants to suppress, everything else is advertising.
    - Lord Northcliffe, publisher of the Daily Mail
     
  4. Dave

    Dave Flightless Bird

    "Al Dykes" <adykes@panix.com> wrote in message
    news:hnte9u$hj5$1@panix5.panix.com...
    > In article <4BA21369.4000402@invalid.invalid>,
    > LouB <Lou@invalid.invalid> wrote:
    >>Al Dykes wrote:
    >>> Does a 32-bit application run on a 64 bit machine use any sort of a
    >>> compatibility layer, not that this is a horrible thing.
    >>>
    >>> Has anyone benchmarked the performance of a heavy application such as
    >>> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>>
    >>> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>>
    >>>
    >>>

    >>The main advantage of 64 bit is that it allows use of large amonts of
    >>memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >>might help.

    >
    >
    > I understand that and know that 32 bit apps are compiled into segments
    > and the is overhear in inter-segment calls. From what I know of
    > mainframe memory, the 64 bit flat memory model is a win for apps that
    > are compiled for it.
    >
    > My question stands, is there any sore of compatibility layer between a
    > 32 bit app and 64-bit Windows?
    >
    >
    > --
    > Al Dykes
    > News is something someone wants to suppress, everything else is
    > advertising.
    > - Lord Northcliffe, publisher of the Daily Mail
    >

    Can't answer the question, but I ran 32 bit Photoshop in a 64 bit OS and it
    seemed to run fine. Did not do any benchmarks. When I got 64 bit Photoshop
    it seems to be faster when dealing with large documents so what Lou posted
    would be applicable here. Again, I didn't do any benchmarks.
    HTH,
    Dave
     
  5. Jasper

    Jasper Flightless Bird

    "Dave" <davidj92@wowway.com> wrote in message
    news:M-adnQhv-ZP6xD_WnZ2dnUVZ_hidnZ2d@sigecom.net...
    >
    >
    > "Al Dykes" <adykes@panix.com> wrote in message
    > news:hnte9u$hj5$1@panix5.panix.com...
    >> In article <4BA21369.4000402@invalid.invalid>,
    >> LouB <Lou@invalid.invalid> wrote:
    >>>Al Dykes wrote:
    >>>> Does a 32-bit application run on a 64 bit machine use any sort of a
    >>>> compatibility layer, not that this is a horrible thing.
    >>>>
    >>>> Has anyone benchmarked the performance of a heavy application such as
    >>>> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>>>
    >>>> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>>>
    >>>>
    >>>>
    >>>The main advantage of 64 bit is that it allows use of large amonts of
    >>>memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >>>might help.

    >>
    >>
    >> I understand that and know that 32 bit apps are compiled into segments
    >> and the is overhear in inter-segment calls. From what I know of
    >> mainframe memory, the 64 bit flat memory model is a win for apps that
    >> are compiled for it.
    >>
    >> My question stands, is there any sore of compatibility layer between a
    >> 32 bit app and 64-bit Windows?
    >>
    >>
    >> --
    >> Al Dykes
    >> News is something someone wants to suppress, everything else is
    >> advertising.
    >> - Lord Northcliffe, publisher of the Daily Mail
    >>

    > Can't answer the question, but I ran 32 bit Photoshop in a 64 bit OS and
    > it seemed to run fine. Did not do any benchmarks. When I got 64 bit
    > Photoshop it seems to be faster when dealing with large documents so what
    > Lou posted would be applicable here. Again, I didn't do any benchmarks.
    > HTH,
    > Dave


    64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    support 16bit so you cant run 16bit apps on 64Bit Windows.

    From my own experiance 32bit apps on 64bit run as fast as on 32bit Windows.

    http://en.wikipedia.org/wiki/Windows_on_Windows
     
  6. Dave

    Dave Flightless Bird

    "Jasper" <noone@nowhere.org> wrote in message
    news:hntmvh$1rr$1@speranza.aioe.org...
    >
    > "Dave" <davidj92@wowway.com> wrote in message
    > news:M-adnQhv-ZP6xD_WnZ2dnUVZ_hidnZ2d@sigecom.net...
    >>
    >>
    >> "Al Dykes" <adykes@panix.com> wrote in message
    >> news:hnte9u$hj5$1@panix5.panix.com...
    >>> In article <4BA21369.4000402@invalid.invalid>,
    >>> LouB <Lou@invalid.invalid> wrote:
    >>>>Al Dykes wrote:
    >>>>> Does a 32-bit application run on a 64 bit machine use any sort of a
    >>>>> compatibility layer, not that this is a horrible thing.
    >>>>>
    >>>>> Has anyone benchmarked the performance of a heavy application such as
    >>>>> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>>>>
    >>>>> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>>>>
    >>>>>
    >>>>>
    >>>>The main advantage of 64 bit is that it allows use of large amonts of
    >>>>memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >>>>might help.
    >>>
    >>>
    >>> I understand that and know that 32 bit apps are compiled into segments
    >>> and the is overhear in inter-segment calls. From what I know of
    >>> mainframe memory, the 64 bit flat memory model is a win for apps that
    >>> are compiled for it.
    >>>
    >>> My question stands, is there any sore of compatibility layer between a
    >>> 32 bit app and 64-bit Windows?
    >>>
    >>>
    >>> --
    >>> Al Dykes
    >>> News is something someone wants to suppress, everything else is
    >>> advertising.
    >>> - Lord Northcliffe, publisher of the Daily Mail
    >>>

    >> Can't answer the question, but I ran 32 bit Photoshop in a 64 bit OS and
    >> it seemed to run fine. Did not do any benchmarks. When I got 64 bit
    >> Photoshop it seems to be faster when dealing with large documents so what
    >> Lou posted would be applicable here. Again, I didn't do any benchmarks.
    >> HTH,
    >> Dave

    >
    > 64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    > applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    > support 16bit so you cant run 16bit apps on 64Bit Windows.
    >
    > From my own experiance 32bit apps on 64bit run as fast as on 32bit
    > Windows.
    >
    > http://en.wikipedia.org/wiki/Windows_on_Windows
    >

    Thanks Jasper, that would explain what (one of) the technical differences
    are between 32 bit and 64 bit Windows. First intelligent answer I've seen
    since that question was posted in a different thread.
    Dave
     
  7. Char Jackson

    Char Jackson Flightless Bird

    On Thu, 18 Mar 2010 11:12:28 -0600, "Jasper" <noone@nowhere.org>
    wrote:

    >64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    >support 16bit so you cant run 16bit apps on 64Bit Windows.


    Thanks, that's good to know. I have a 16-bit checkers game that I've
    dragged along through 15 years of upgrades. I guess if/when I move to
    a 64-bit platform I'll finally have to leave it behind.
     
  8. Tim Slattery

    Tim Slattery Flightless Bird

    Char Jackson <none@none.invalid> wrote:

    >On Thu, 18 Mar 2010 11:12:28 -0600, "Jasper" <noone@nowhere.org>
    >wrote:
    >
    >>64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >>applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    >>support 16bit so you cant run 16bit apps on 64Bit Windows.

    >
    >Thanks, that's good to know. I have a 16-bit checkers game that I've
    >dragged along through 15 years of upgrades. I guess if/when I move to
    >a 64-bit platform I'll finally have to leave it behind.


    Not necessarily. Check www.dosbox.com, a free DOS emulator. They say
    it runs on 64-bit Vista, which doesn't run 16-bit programs, so I'd
    guess it will run on 64-bit Win7 also.

    --
    Tim Slattery
    Slattery_T@bls.gov
    http://members.cox.net/slatteryt
     
  9. Zaphod Beeblebrox

    Zaphod Beeblebrox Flightless Bird

    "Tim Slattery" <Slattery_T@bls.gov> wrote in message
    news:4325q5p4cm4paheu0158mqm88mqho379tg@4ax.com...
    > Char Jackson <none@none.invalid> wrote:
    >
    >>On Thu, 18 Mar 2010 11:12:28 -0600, "Jasper" <noone@nowhere.org>
    >>wrote:
    >>
    >>>64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >>>applications. 32bit Windows uses WoW to run 16bit apps. WoW64
    >>>dropped
    >>>support 16bit so you cant run 16bit apps on 64Bit Windows.

    >>
    >>Thanks, that's good to know. I have a 16-bit checkers game that I've
    >>dragged along through 15 years of upgrades. I guess if/when I move
    >>to
    >>a 64-bit platform I'll finally have to leave it behind.

    >
    > Not necessarily. Check www.dosbox.com, a free DOS emulator. They say
    > it runs on 64-bit Vista, which doesn't run 16-bit programs, so I'd
    > guess it will run on 64-bit Win7 also.
    >


    Also, AIUI the XP Mode add-on for Windows 7 (if your hardware supports
    it) is 32-bit so you can run it that way.

    It's amazing how far we've come, isn't it? We are casually discussing
    how to run a 16-bit app in an emulator on a 32-bit emulator inside of
    a 64-bit OS.

    --
    Zaphod

    Vell, Zaphod's just zis guy, ya know? - Gag Halfrunt
     
  10. Char Jackson

    Char Jackson Flightless Bird

    On Thu, 18 Mar 2010 16:43:32 -0400, "Zaphod Beeblebrox"
    <Zaphod.Arisztid.Beeblebrox@gmail.com> wrote:

    >
    >"Tim Slattery" <Slattery_T@bls.gov> wrote in message
    >news:4325q5p4cm4paheu0158mqm88mqho379tg@4ax.com...
    >> Char Jackson <none@none.invalid> wrote:
    >>
    >>>On Thu, 18 Mar 2010 11:12:28 -0600, "Jasper" <noone@nowhere.org>
    >>>wrote:
    >>>
    >>>>64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >>>>applications. 32bit Windows uses WoW to run 16bit apps. WoW64
    >>>>dropped
    >>>>support 16bit so you cant run 16bit apps on 64Bit Windows.
    >>>
    >>>Thanks, that's good to know. I have a 16-bit checkers game that I've
    >>>dragged along through 15 years of upgrades. I guess if/when I move
    >>>to
    >>>a 64-bit platform I'll finally have to leave it behind.

    >>
    >> Not necessarily. Check www.dosbox.com, a free DOS emulator. They say
    >> it runs on 64-bit Vista, which doesn't run 16-bit programs, so I'd
    >> guess it will run on 64-bit Win7 also.
    >>

    >
    >Also, AIUI the XP Mode add-on for Windows 7 (if your hardware supports
    >it) is 32-bit so you can run it that way.
    >
    >It's amazing how far we've come, isn't it? We are casually discussing
    >how to run a 16-bit app in an emulator on a 32-bit emulator inside of
    >a 64-bit OS.


    Thanks, guys. :) Yes, we've come a long way indeed.
     
  11. Al Dykes

    Al Dykes Flightless Bird

    In article <hntmvh$1rr$1@speranza.aioe.org>, Jasper <noone@nowhere.org> wrote:
    >
    >"Dave" <davidj92@wowway.com> wrote in message
    >news:M-adnQhv-ZP6xD_WnZ2dnUVZ_hidnZ2d@sigecom.net...
    >>
    >>
    >> "Al Dykes" <adykes@panix.com> wrote in message
    >> news:hnte9u$hj5$1@panix5.panix.com...
    >>> In article <4BA21369.4000402@invalid.invalid>,
    >>> LouB <Lou@invalid.invalid> wrote:
    >>>>Al Dykes wrote:
    >>>>> Does a 32-bit application run on a 64 bit machine use any sort of a
    >>>>> compatibility layer, not that this is a horrible thing.
    >>>>>
    >>>>> Has anyone benchmarked the performance of a heavy application such as
    >>>>> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>>>>
    >>>>> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>>>>
    >>>>>
    >>>>>
    >>>>The main advantage of 64 bit is that it allows use of large amonts of
    >>>>memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >>>>might help.
    >>>
    >>>
    >>> I understand that and know that 32 bit apps are compiled into segments
    >>> and the is overhear in inter-segment calls. From what I know of
    >>> mainframe memory, the 64 bit flat memory model is a win for apps that
    >>> are compiled for it.
    >>>
    >>> My question stands, is there any sore of compatibility layer between a
    >>> 32 bit app and 64-bit Windows?
    >>>
    >>>
    >>> --
    >>> Al Dykes
    >>> News is something someone wants to suppress, everything else is
    >>> advertising.
    >>> - Lord Northcliffe, publisher of the Daily Mail
    >>>

    >> Can't answer the question, but I ran 32 bit Photoshop in a 64 bit OS and
    >> it seemed to run fine. Did not do any benchmarks. When I got 64 bit
    >> Photoshop it seems to be faster when dealing with large documents so what
    >> Lou posted would be applicable here. Again, I didn't do any benchmarks.
    >> HTH,
    >> Dave

    >
    >64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    >support 16bit so you cant run 16bit apps on 64Bit Windows.
    >
    >From my own experiance 32bit apps on 64bit run as fast as on 32bit Windows.
    >
    >http://en.wikipedia.org/wiki/Windows_on_Windows
    >


    http://en.wikipedia.org/wiki/WoW64



    --
    Al Dykes
    News is something someone wants to suppress, everything else is advertising.
    - Lord Northcliffe, publisher of the Daily Mail
     
  12. GreyCloud

    GreyCloud Flightless Bird

    Dave wrote:
    >
    >
    > "Jasper" <noone@nowhere.org> wrote in message
    > news:hntmvh$1rr$1@speranza.aioe.org...
    >>
    >> "Dave" <davidj92@wowway.com> wrote in message
    >> news:M-adnQhv-ZP6xD_WnZ2dnUVZ_hidnZ2d@sigecom.net...
    >>>
    >>>
    >>> "Al Dykes" <adykes@panix.com> wrote in message
    >>> news:hnte9u$hj5$1@panix5.panix.com...
    >>>> In article <4BA21369.4000402@invalid.invalid>,
    >>>> LouB <Lou@invalid.invalid> wrote:
    >>>>> Al Dykes wrote:
    >>>>>> Does a 32-bit application run on a 64 bit machine use any sort of a
    >>>>>> compatibility layer, not that this is a horrible thing.
    >>>>>>
    >>>>>> Has anyone benchmarked the performance of a heavy application such as
    >>>>>> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>>>>>
    >>>>>> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>>>>>
    >>>>>>
    >>>>>>
    >>>>> The main advantage of 64 bit is that it allows use of large amonts of
    >>>>> memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >>>>> might help.
    >>>>
    >>>>
    >>>> I understand that and know that 32 bit apps are compiled into segments
    >>>> and the is overhear in inter-segment calls. From what I know of
    >>>> mainframe memory, the 64 bit flat memory model is a win for apps that
    >>>> are compiled for it.
    >>>>
    >>>> My question stands, is there any sore of compatibility layer between a
    >>>> 32 bit app and 64-bit Windows?
    >>>>
    >>>>
    >>>> --
    >>>> Al Dykes
    >>>> News is something someone wants to suppress, everything else is
    >>>> advertising.
    >>>> - Lord Northcliffe, publisher of the Daily Mail
    >>>>
    >>> Can't answer the question, but I ran 32 bit Photoshop in a 64 bit OS
    >>> and it seemed to run fine. Did not do any benchmarks. When I got 64
    >>> bit Photoshop it seems to be faster when dealing with large documents
    >>> so what Lou posted would be applicable here. Again, I didn't do any
    >>> benchmarks.
    >>> HTH,
    >>> Dave

    >>
    >> 64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >> applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    >> support 16bit so you cant run 16bit apps on 64Bit Windows.
    >>
    >> From my own experiance 32bit apps on 64bit run as fast as on 32bit
    >> Windows.
    >>
    >> http://en.wikipedia.org/wiki/Windows_on_Windows
    >>

    > Thanks Jasper, that would explain what (one of) the technical
    > differences are between 32 bit and 64 bit Windows. First intelligent
    > answer I've seen since that question was posted in a different thread.
    > Dave


    There is one more advantage to 64-bit that seems to have escaped many
    people: any program compiled on a 64-bit Intel processor gets to have
    access to the extra 8 general purpose registers. These extra registers
    are faster than the cache memory on the chip and faster than having to
    store temporary results from a calculation into main ram. That is of
    course if the compiler compiles the app as a 64-bit app.
    32-bit apps can't access the extra 8 general purpose registers, so there
    is more overhead.
     
  13. LouB

    LouB Flightless Bird

    GreyCloud wrote:
    > Dave wrote:
    >>
    >>
    >> "Jasper" <noone@nowhere.org> wrote in message
    >> news:hntmvh$1rr$1@speranza.aioe.org...
    >>>
    >>> "Dave" <davidj92@wowway.com> wrote in message
    >>> news:M-adnQhv-ZP6xD_WnZ2dnUVZ_hidnZ2d@sigecom.net...
    >>>>
    >>>>
    >>>> "Al Dykes" <adykes@panix.com> wrote in message
    >>>> news:hnte9u$hj5$1@panix5.panix.com...
    >>>>> In article <4BA21369.4000402@invalid.invalid>,
    >>>>> LouB <Lou@invalid.invalid> wrote:
    >>>>>> Al Dykes wrote:
    >>>>>>> Does a 32-bit application run on a 64 bit machine use any sort of a
    >>>>>>> compatibility layer, not that this is a horrible thing.
    >>>>>>>
    >>>>>>> Has anyone benchmarked the performance of a heavy application
    >>>>>>> such as
    >>>>>>> 32-bit Photoshop under 32-bit and 64-bit Windows?
    >>>>>>>
    >>>>>>> (I dunno if there *is* a 64-bit build of Photoshop yet.)
    >>>>>>>
    >>>>>>>
    >>>>>>>
    >>>>>> The main advantage of 64 bit is that it allows use of large amonts of
    >>>>>> memory easily. So if Photoshop likes to use a loy of memory 64 bit
    >>>>>> might help.
    >>>>>
    >>>>>
    >>>>> I understand that and know that 32 bit apps are compiled into segments
    >>>>> and the is overhear in inter-segment calls. From what I know of
    >>>>> mainframe memory, the 64 bit flat memory model is a win for apps that
    >>>>> are compiled for it.
    >>>>>
    >>>>> My question stands, is there any sore of compatibility layer between a
    >>>>> 32 bit app and 64-bit Windows?
    >>>>>
    >>>>>
    >>>>> --
    >>>>> Al Dykes
    >>>>> News is something someone wants to suppress, everything else is
    >>>>> advertising.
    >>>>> - Lord Northcliffe, publisher of the Daily Mail
    >>>>>
    >>>> Can't answer the question, but I ran 32 bit Photoshop in a 64 bit OS
    >>>> and it seemed to run fine. Did not do any benchmarks. When I got 64
    >>>> bit Photoshop it seems to be faster when dealing with large
    >>>> documents so what Lou posted would be applicable here. Again, I
    >>>> didn't do any benchmarks.
    >>>> HTH,
    >>>> Dave
    >>>
    >>> 64 bit Windows uses WoW64 (Windoes on Windows) for running 32bit
    >>> applications. 32bit Windows uses WoW to run 16bit apps. WoW64 dropped
    >>> support 16bit so you cant run 16bit apps on 64Bit Windows.
    >>>
    >>> From my own experiance 32bit apps on 64bit run as fast as on 32bit
    >>> Windows.
    >>>
    >>> http://en.wikipedia.org/wiki/Windows_on_Windows
    >>>

    >> Thanks Jasper, that would explain what (one of) the technical
    >> differences are between 32 bit and 64 bit Windows. First intelligent
    >> answer I've seen since that question was posted in a different thread.
    >> Dave

    >
    > There is one more advantage to 64-bit that seems to have escaped many
    > people: any program compiled on a 64-bit Intel processor gets to have
    > access to the extra 8 general purpose registers. These extra registers
    > are faster than the cache memory on the chip and faster than having to
    > store temporary results from a calculation into main ram. That is of
    > course if the compiler compiles the app as a 64-bit app.
    > 32-bit apps can't access the extra 8 general purpose registers, so there
    > is more overhead.


    Thanks
     
  14. Dave

    Dave Flightless Bird

    "GreyCloud" <mist@cumulus.com> wrote in message
    snip

    >> Thanks Jasper, that would explain what (one of) the technical differences
    >> are between 32 bit and 64 bit Windows. First intelligent answer I've seen
    >> since that question was posted in a different thread.
    >> Dave

    >
    > There is one more advantage to 64-bit that seems to have escaped many
    > people: any program compiled on a 64-bit Intel processor gets to have
    > access to the extra 8 general purpose registers. These extra registers
    > are faster than the cache memory on the chip and faster than having to
    > store temporary results from a calculation into main ram. That is of
    > course if the compiler compiles the app as a 64-bit app.
    > 32-bit apps can't access the extra 8 general purpose registers, so there
    > is more overhead.


    Thanks, that makes it more logical to run 64 bit if you have a capable
    machine.
    What I was referring to was a post where the OP wanted to install 32 bit and
    64 bit Windows on the same machine. My point was if you have the 64 bit OS
    then you can run any 32 bit program or 64 bit program so (implied) you
    really don't need the 32 bit since you have and can utilize the 64 bit.
    I got called on this and was told I was wrong, replied with a request to
    explain why that was so and no response.
    So, it looks like the only limitation so far is the ability to run 16 bit
    programs native on a 64 bit OS, but if the emulator will run the 16 bit
    programs then it's probably back to 64 bit being the way to go.
    Just my thoughts,
    Dave
     
  15. Yousuf Khan

    Yousuf Khan Flightless Bird

    Al Dykes wrote:
    > Does a 32-bit application run on a 64 bit machine use any sort of a
    > compatibility layer, not that this is a horrible thing.
    >
    > Has anyone benchmarked the performance of a heavy application such as
    > 32-bit Photoshop under 32-bit and 64-bit Windows?
    >
    > (I dunno if there *is* a 64-bit build of Photoshop yet.)


    As others have pointed out, WoW64 is what is used to run 32-bit apps
    under 64-bit Windows. However, it's not an emulation layer, it's just a
    remapping layer. In computer science they call it "thunking". It takes
    32-bit application calls and simply redirects them to the 64-bit API,
    properly formatted and mapped to the right memory addresses. All 32-bit
    system DLL's are simply just stub binaries that do this thunking,
    passing it on to the appropriate 64-bit DLL's.

    One thing to note is that all 32-bit apps will be mapped to their own
    individual full 32-bit environment in 64-bit Windows. In a native 32-bit
    Windows, each app would get only a partial section of a single 32-bit
    memory map. So each app will think it is the only thing running on the
    machine and have access to more memory by themselves.

    So regarding whether there is a performance difference between 32-bit
    apps in 64-bit Windows, it probably depends on what the 32-bit app is
    limited by. If the app makes a lot of system calls, then it might be
    limited by the thunking process, which I expect to add maybe less than
    1% in overhead to the system calls. If the app is memory limited, then
    it's going to find it's faster under 64-bit Windows.

    Yousuf Khan
     
  16. Zootal

    Zootal Flightless Bird


    > Not necessarily. Check www.dosbox.com, a free DOS emulator. They say
    > it runs on 64-bit Vista, which doesn't run 16-bit programs, so I'd
    > guess it will run on 64-bit Win7 also.
    >


    Dosbox works great on 64 bit Windows 7. And for stuff that doesn't run in
    Dosbox, you can use VirtualBox (http://www.virtualbox.org/). I run Win2000
    in a VirtualBox VM for the few things I want that don't run in Win7 64 bit
    or dosbox.
     
  17. GreyCloud

    GreyCloud Flightless Bird

    Dave wrote:
    >
    >
    > "GreyCloud" <mist@cumulus.com> wrote in message
    > snip
    >
    >>> Thanks Jasper, that would explain what (one of) the technical
    >>> differences are between 32 bit and 64 bit Windows. First intelligent
    >>> answer I've seen since that question was posted in a different thread.
    >>> Dave

    >>
    >> There is one more advantage to 64-bit that seems to have escaped many
    >> people: any program compiled on a 64-bit Intel processor gets to have
    >> access to the extra 8 general purpose registers. These extra
    >> registers are faster than the cache memory on the chip and faster than
    >> having to store temporary results from a calculation into main ram.
    >> That is of course if the compiler compiles the app as a 64-bit app.
    >> 32-bit apps can't access the extra 8 general purpose registers, so
    >> there is more overhead.

    >
    > Thanks, that makes it more logical to run 64 bit if you have a capable
    > machine.
    > What I was referring to was a post where the OP wanted to install 32 bit
    > and 64 bit Windows on the same machine. My point was if you have the 64
    > bit OS then you can run any 32 bit program or 64 bit program so
    > (implied) you really don't need the 32 bit since you have and can
    > utilize the 64 bit.
    > I got called on this and was told I was wrong, replied with a request to
    > explain why that was so and no response.
    > So, it looks like the only limitation so far is the ability to run 16
    > bit programs native on a 64 bit OS, but if the emulator will run the 16
    > bit programs then it's probably back to 64 bit being the way to go.
    > Just my thoughts,
    > Dave


    I'm sure that the old 16-bit programs can be run somehow on win7.
    Searching around with google usually yields pretty good results.
     
  18. Zootal

    Zootal Flightless Bird

    > Thanks, that makes it more logical to run 64 bit if you have a capable
    > machine.
    > What I was referring to was a post where the OP wanted to install 32
    > bit and 64 bit Windows on the same machine. My point was if you have
    > the 64 bit OS then you can run any 32 bit program or 64 bit program so
    > (implied) you really don't need the 32 bit since you have and can
    > utilize the 64 bit. I got called on this and was told I was wrong,
    > replied with a request to explain why that was so and no response.
    > So, it looks like the only limitation so far is the ability to run 16
    > bit programs native on a 64 bit OS, but if the emulator will run the
    > 16 bit programs then it's probably back to 64 bit being the way to go.
    > Just my thoughts,
    > Dave
    >
    >


    The other limitation is the lack of drivers for one-off and older hardware.
    I have a few odds and ends laying around that I can't use with XP 64 of
    Windows 7 64. I have a spare machine with XP32 for those things - video
    capture devices, a few older webcams, and a couple of bluetooth dongles, to
    be precise. None of them work with 64 bit XP or Win7.
     
  19. Dave

    Dave Flightless Bird

    "Zootal" <nospam@spam.zootal.nospam.com> wrote in message
    news:Xns9D40BBE37C006nospamspamzootalnosp@216.196.97.131...
    >> Thanks, that makes it more logical to run 64 bit if you have a capable
    >> machine.
    >> What I was referring to was a post where the OP wanted to install 32
    >> bit and 64 bit Windows on the same machine. My point was if you have
    >> the 64 bit OS then you can run any 32 bit program or 64 bit program so
    >> (implied) you really don't need the 32 bit since you have and can
    >> utilize the 64 bit. I got called on this and was told I was wrong,
    >> replied with a request to explain why that was so and no response.
    >> So, it looks like the only limitation so far is the ability to run 16
    >> bit programs native on a 64 bit OS, but if the emulator will run the
    >> 16 bit programs then it's probably back to 64 bit being the way to go.
    >> Just my thoughts,
    >> Dave
    >>
    >>

    >
    > The other limitation is the lack of drivers for one-off and older
    > hardware.
    > I have a few odds and ends laying around that I can't use with XP 64 of
    > Windows 7 64. I have a spare machine with XP32 for those things - video
    > capture devices, a few older webcams, and a couple of bluetooth dongles,
    > to
    > be precise. None of them work with 64 bit XP or Win7.


    Don't know much about this, but OP wanted to install 32 and 64 bit on one
    box. If it were possible to install 32 bit and 64 bit both on one machine
    then I assume you'd be able to run older stuff by booting into 32 bit?
     
  20. John

    John Flightless Bird

    On Fri, 19 Mar 2010 20:27:26 -0500, Zootal
    <nospam@spam.zootal.nospam.com> wrote:

    >> Thanks, that makes it more logical to run 64 bit if you have a capable
    >> machine.
    >> What I was referring to was a post where the OP wanted to install 32
    >> bit and 64 bit Windows on the same machine. My point was if you have
    >> the 64 bit OS then you can run any 32 bit program or 64 bit program so
    >> (implied) you really don't need the 32 bit since you have and can
    >> utilize the 64 bit. I got called on this and was told I was wrong,
    >> replied with a request to explain why that was so and no response.
    >> So, it looks like the only limitation so far is the ability to run 16
    >> bit programs native on a 64 bit OS, but if the emulator will run the
    >> 16 bit programs then it's probably back to 64 bit being the way to go.
    >> Just my thoughts,
    >> Dave
    >>
    >>

    >
    >The other limitation is the lack of drivers for one-off and older hardware.
    >I have a few odds and ends laying around that I can't use with XP 64 of
    >Windows 7 64. I have a spare machine with XP32 for those things - video
    >capture devices, a few older webcams, and a couple of bluetooth dongles, to
    >be precise. None of them work with 64 bit XP or Win7.



    I had assumed the same thing with a usb->rs232 connection - old device
    - no w7 driver. However doing a search for RS232 - USB turned up a
    vendor selling what appeared as the same device and who offered a Win7
    driver. I installed that driver and things worked. It seems that
    nearly everyone is offering Win7 support and since many devices, of
    the same type, may well be built using the same internals it is
    possible that with a little effort that most things can be made to
    work with 7.

    John B.
     

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