What is the difference between 64 bit and 32 bit processor?

1. 68

   anusujithposted 13 years ago

   What is the difference between 64 bit and 32 bit processor?
   
   is quite familiar, 64-bit and 32-bit processors. What is the major difference between these two?

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2. 63

   Manna in the wildposted 13 years ago

   The first computers and simple calculators were only 4 bit. This essentially means they could only index 2^4 = 32 unique entries in a table using only those 4 bits. It specifically describes the so called 'width' of the address bus. A bus is simply a set of parallel wires that convey signals from one place in the computer to another. Clearly, a wider bus will permit you to move more data at once, and also address more objects with a single index. Specifically, the address bus is important because this dictates how much memory you can address using one data-transfer of an address. This address is really an index into memory. So an 8-bit computer could address a memory size of 2^8=256 bytes. This is still very restrictive, so engineers quickly doubled that to 32 bits which addresses a more respectable 2^32=4 294 967 296 bytes. The complexity of the CPU and motherboards tends to rise as the bus width is increased and the 32 bus has persisted for many years.
   
   A 64 bit computer doubles this again permitting memory sizes that are addressable in one address to 2^64 = 1.8 x 10^19 which is a very large space.
   
   Programs compiled to run on 64 bit computers will not run on 32 bit computers, but a program compiled to run on a 64 bit computer can often run by using a compatibility mode or translator.
   
   In broad terms, providing all the drivers and software works for you, a 64 bit computer will allow much more memory to be available to an operating system and its programs, and should run faster and more efficiently than a 32 bit system.

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