I am trying to run a memory intensive program which requires more than 4 GB memory. I am running it on a 64 bit processor, and I have 16 GB RAM (which is also visible to me). But the program crashes. So I am unable to use more than 4GB for one process on a 64bit processor. How do I solve this problem?

Edit: The thing is the processor is 64 bit and the OS supports a 64 bit processor. And I am trying to run C code which requires lots of memory as it's a video processing code. But it crashes when the memory required goes above 4 GB, even though 16 GB RAM is visible.

The operating system is Windows Server 2003.

  • 2
    Which operating system? Which compiler?
    – Harriv
    Nov 12, 2009 at 12:33
  • 3
    More details please, are you writing 32-bit or 64-bit app? 32-bit or 64-bit OS?
    – Artelius
    Nov 12, 2009 at 12:33
  • 1
    If you don't want to get this migrated to Super User, edit your question to make it clear that you're developing an application
    – ChrisF
    Nov 12, 2009 at 12:37
  • I once had a software (Macromedia Fontographer, last version) that immediately crashed after starting, as soon as the PC (windows) had more than 1 GB of RAM.
    – Martin
    Nov 12, 2009 at 12:54
  • Why do these questions end up on SU like this? Can't anybody edit them properly before migrating them? This whole question is a mess, frankly.
    – alex
    Nov 12, 2009 at 13:00

1 Answer 1


If your program is a 32-bit program, it won't be able to use more than 4GB, regardless of the processor or OS you run it on...

Do you know for sure that your program is compiled as 64-bit, and that you're running it on a 64-bit OS?

It's hard to tell from the question, but are you expecting to run some off-the-shelf software and have it use more than 4GB of RAM? That's not going to work unless it's specifically compiled for 64-bit, which most off-the-shelf Windows software isn't.

  • 1
    32-bit programs can only use 2GB of RAM (3GB on 32-bit OS/4GB on 64-bit OS with /LARGEADDRESSAWARE linking flag on)
    – phuclv
    Aug 30, 2013 at 8:44

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