If you're still running 32 bit applications on a 64 bit operating system, you may know there are some options for increasing the amount of memory that the application can access.
While a 32 bit application has the address range to see 4 GB of memory, by default they are limited to 2 GB of memory, leaving the other 2 GB available to the operating system. This was primarily due to the 4 GB restriction on addressable memory on 32 bit operating systems. Once you're on a 64 bit operating system with more than 4 GB of memory though, there's no point in that default restriction.
What it all boils down to is setting a flag in the program's executable that tells the operating system that the application can handle larger addressable memory. In particular, the editbin tool that comes with Visual Studio allows you to pass a /LARGEADDRESSAWARE flag to modify a program executable so that flag is set.
However, if you don't have Visual Studio, or you do but you want an easier way to handle this, then look at the 4GB Patch tool from NTCore. The utility is free, simple to use and makes a backup copy of the executable prior to making the modification.