

If you can't recompile your custom program for 64-bit mode, it should be able to run in 32-bit mode thanks to the WoW64 compatibility layer.ĭownsides: you'll have to do a custom install of the OS (meaning you basically start from scratch). This allows the OS to address all of your RAM, and is really the right way to solve the problem. There are several ways to make more RAM accessible to your program: Since your new iMac has a bigger, better video card (with more video memory), it takes up more of the 4GB address space and there's less left for actual RAM. The problem is that "stuff" doesn't just include RAM, it includes RAM and memory-mapped I/O, most notably the video card.


First, let me explain the problem a little: in 32-bit mode, the processor can only address 4GB of stuff.
