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Asked: 2026-05-11T05:42:39+00:00

From what I understand, a 32-bit process can only access 2 GB of memory

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From what I understand, a 32-bit process can only access 2 GB of memory on 32-bit Windows without the /3GB switch, and that some of that memory is taken up by the OS for its own diabolical reasons. This seems to mesh with my experience as we have an app that crashes when it reaches around 1.2 – 1.5 GB of RAM without memory exceptions, even though there is still plenty of memory available.

Would moving this 32-bit application to 64-bit Windows allowing it accesses more than 1.5 GB it can now? Would the application itself have to be upgraded to 64-bit?

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  1. Newer versions of Visual Studio have a new flag which make 32-bit apps ‘big address space aware’. Basically what it does is say that if it’s loaded on a 64-bit version of windows, then it will get 4GB (the limit of 32-bit pointers). This is certainly better than the 2 or 3 GB you get on 32-bit versions of windows. See http://msdn.microsoft.com/en-us/library/aa366778.aspx:

    Most notably it says:

    Limits on memory and address space vary by platform, operating system, and by whether the IMAGE_FILE_LARGE_ADDRESS_AWARE value of the LOADED_IMAGE structure and 4-gigabyte tuning (4GT) are in use. IMAGE_FILE_LARGE_ADDRESS_AWARE is set or cleared by using the /LARGEADDRESSAWARE linker option.

    Also see: http://msdn.microsoft.com/en-us/library/wz223b1z.aspx

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