A 32-bit computer is capable of dealing with instructions and allocates memory locations with the length of 32 bits (digits 0 and 1).
Giving that each bit the number 0 or 1, the total number of combinations is 232, which is 4,294,967,295 (4.29 billion).
Each location, out of these 4.29 billion, are capable of storing 1 byte of data. If we convert that value, we will get around 4,096MB or 3,99GB of data.
That is why 32-bit processor can access a maximum of 4GB of physical memory by default.
That is the biggest difference between 32-bit and 64-bit operating systems. The 32-bit version can only address a bit less than 4GB of physical memory, in total, for the entire system – including the memory in your video card as well.
64-bit versions of Windows can access 2000GB of RAM. Modern desktop and laptop computers generally have at least 8GB of RAM, so we are nowhere near the limit of what a 64-bit processor can access.
Among other benefits, a 64-bit processor can calculate individual tasks two (or more) times as fast as a 32-bit CPU model. A 64-bit software is designed to take advantage of these features and speed and performance improvements are more noticeable on software which is capable of using a lot of CPU power.
These benefits can only be fully obtained if the software that you install is actually designed to use all the features of the 64-bit hardware architecture.
I would advise you to use a 64-bit software on a 64-bit system if there is a 64-bit version available. This way you will experience much better stability and performance in everyday work.