This is primary used processor of the world. World's most popular manufacturers Intel and AMD used this technology for long time. It used till early 1990's. Those days we used operating systems and software which require less physical memory and less speed. 32-bit processors can address for about 4 GB of memory in one time.
64-bit processor
Founding of 64-bit processor on 1961 for IBM 7030 Stretch supercomputer. But it introduced to PCs in 2000. When 32-bit was not enough to process some applications, 64-bit was developed. A 64-bit processor can run both 32 and 64-bit applications and operating systems. But 32-bit processor can only run 32-bit operating systems and applications.
What is the difference between 32-bit and 64-bit processors
64-bit can do more calculations than 32-bit per second. This really effects the speed of the entire computer system. 64-bit processors comes with dual core, quad core, six core and eight core in technology. 64-bit can handle more memory than 32-bit. 32-bit can only handle up to 4GB memory but 64-bit can handle more than 4GB memory at a time. This is very important because it can do many calculations at a time and able increase the performance.
When working with games and 3D graphics it is not so helpful to transferring from 32-bit to 64-bit processor. It is better to increase the memory of the video adaptor.