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• 01-25-2007, 10:18 AM

  Tharriso Joined on 10-16-2006, 7:00 PM Posts 21 Tharriso

  Questions regarding 64 bit windows and virtual memory allocations Reply Contact Hey guys, just need some clarification on a couple points regarding virtual memory and x64 editions of Windows.  Due to poor design, we have an application that has a real problem with out of memory errors.  I have worked with Microsoft product support on this, and one of the suggestions was to move to 64 bit Windows and run in WOW64 mode.   It is my understanding that running 32 bit apps on 64 bit windows will not offer you any advantages with virtual memory unless that app is designed to use the extra memory by being compiled with the LARGEMEMORYAWARE switch.  If it is designed to take advantage of it, then that 32 bit app would be allocated up to 4GB of virtual memory when running on 64 bit.  If the app was designed to run in 64 bit natively, then it would be allocated up to 8TB of virtual memory space.  Is this correct?

• 01-29-2007, 12:31 PM

  In reply to

  thomad Joined on 08-20-2002, 3:28 PM Redmond Posts 387 thomad

  Re: Questions regarding 64 bit windows and virtual memory allocations Reply Contact Tharriso, W3WP.EXE (the IIS worker process) is compiled with /LARGEADDRESSAWARE. It will take advantage of the 64-Bit benefits and pretty much double your address space (4GB instead of 2). If your application is leaking you might consider IIS memory-based recycling. To switch from 64-Bit to 32-Bit worker processes you should have a look into the "enable32BitAppsOnWin64 switch.  Hope this helps. Thomas Deml Senior Program Manager Internet Information Services Microsoft Corp.