Running 32-bit vs. 64-bit Programs on 64-bit Windows

In short: You won't gain anything. At least it's highly unlikely.

Now, granted, tabbed browsing gobbles up pretty much memory but it still usually comes nowhere near the 4 GiB limit imposed on 32-bit processes on a 64-bit system. Furthermore, you're unlikely to find any plug-ins that work with the 64-bit version. Although the lack of Adobe Flash might just be beneficial for performance ;-)

The only way you'll make the applications work as 64-bit applications is to compile them as 64-bit applications. Til you do that, they'll run as 32-bit. They should work fine, but will have most of the same limitations they've always had.

There are ways to help ensure that code will be compatible with 32- and 64-bit processors. Make sure you don't do int-->pointer and pointer-->int conversions, or rely too much on the size of ints, longs, etc.

If you don't have the original code, you're kinda screwed, and will have to wait for whoever does have the code to release a 64-bit version of the app.