running 32 bit apps on a 64 bit processor?

I am currently running a 64 bit computer (windows and linux) and 32 bit programs work perfectly well. There is however, one challenge. Do you have a 64 bit operating system? If you don't, chances are you are not using the 64 bit capabilities of your processor. If you have a 64 bit OS, you may run into the problem of finding drivers for your hardware. Drivers, unlike applications, cannot be given a 32 bit environment in which to run since they must have access to the core of the OS.

The way that 64 bit works is that the processor architecture was expanded, and the ability to process data 64 bits at a time was added. However, the ability to handle 32 bit commands remains. In fact (assuming you are using the typical current AMD and Intel chips), these 64 bit processors could execute the instructions of an 8086. Thus, (unfortunately in some ways) the current desktop 64 bit processors are not "straight 64 bit" since they include the ability (for backwards compatibility with hardware almost no one uses anymore) to run in the real mode of 8086 processors, virtual real mode, 32-bit protected mode, and extended 64-bit mode.

Overall, you do not need to fear any performance related issues. 32 bit apps really won't be aware that they are running on a 64 bit machine especially if you use a 32 bit OS. On a 64 bit OS, WinXP Pro x64 Edition, 32 bit programs are given 32 bit environments in a manner that neither you nor the software will typically have to be made aware of.

So, you can definitely run 32 bit applications on 64 bit processors without suffering noticeable performance degradation, but neither will you benefit from the ability to use much, much more memory and process data faster.

Not really. 32-bit operating systems normally work just fine on 64-bit CPUs. If you're using a 32-bit OS then use 32-bit apps.