What is the difference between 64-bit and 32-bit Operating systems? [duplicate]

"mainly the amount of RAM accessible. In most 32bit OSs there is a 4gb (closer to 3gb actually) ceiling. I believe vista x64 can access up to 128gb.

Realistically, unless you're a power user it won't matter. Very few activities you'd do on a daily basis will require more than 3gb of memory. Also, driver support for 32bit OSs is slightly better.

64bit apps will not run in a 32bit environment. However, you probably won't find very many apps that are exclusively 64bit. 32bit apps will run fine 99% of the time in x64."

"32 bit vs 64 bit refers to the address space, and as others mentioned this translates into the amount of RAM you can use: 32 bit = 4GB, 64bit has a theoretical ceiling of 16, 384 petabytes. Wow.

The fact that you are posting on superuser probably indicates that you aren't a ""normal"" user. If all you're doing is checking email and writing word docs, you are probably ok with 32-bit; however, if you are buying a new computer and you're not looking for a cheap netbook, I see no real valid reason NOT to go with a 64-bit system. There are, however, many reason to get a 64-bit and thus as much RAM as you can get your grubby hands on, including : compilation performance if you're a programmer, multitasking performance, heavy duty video/graphical editing performance, VM performance, and high-end gaming performance. Notice the keyword performance? If that is important to you in the future, go for 64-bit."