What is 64 bit Operating System ??

There are 64 bit Windows 7 flying around in the market. Actually new computers nowadays are preloaded with the 64 bit version..

The Limitation of 32 Bit Operating System
The old 32 bit version of Windows can only support up to 4 GB of RAM. And one thread (aka one program) can only access up to 2 GB. Doesn't matter how many RAM you put in.... Only 2 GB

History
Somewhere in the year 2000, Intel release this 64 bit CPU called Itanium. But it was too expensive and incompatible with existing 32 bit program.

After that, AMD release AMD 64 CPU. It is not a new design but just a minor extension of the Intel 386 instruction. Because it is cheap it came to wide acceptance.

Itanium are obsolete now. All 64 Bit Operating System and program are designed to run on AMD 64 nowadays.

Is it better ?
64 bit OS and program used twice the RAM comparing with 32 bit. But it run 50 % faster then 32 bit.

64 Bit driver are incompatible with 32 Bit driver. All 64 Bit driver must be signed by Microsoft if you want to install it. No such restriction on Linux.

32 Bit program will run on 64 bit Operating System with 50 % performance decrease. 64 Bit program cannot run on 32 bit Operating System.

Conclusion
If you are a video editor or a serious gamer or a database manager, you will see a big increase in performance of your PC if you upgrade it to 64 Bit. For ordinary users, there is no difference.