What's the difference between 32-bit and 64-bit? When we download software or operating systems, there is usually an option to download either, so there must be importance to the subject.
The terms 32-bit and 64-bit refer to how the processor deals with incoming information. 64-bit technology is newer than 32, and in most cases is backwards compatible with 32-bit software. It can also handle large data sets more efficiently than a 32-bit system can, and address RAM over the 4GB limit, something that 32-bit is incapable of performing. This means more memory for the software running on the system.
To see if your windows installation 32-bit or 64-bit, you can go to start -> control panel -> system and look for the system type. On a mac, this info can be found by clicking the apple -> About This Mac and clicking the button to get more detailed system information.