Hang on to your britches; this one gets a little technical. However, I’ll try to explain this on a basic level. To the truly technical out there among you, I know that I am about to butcher this topic to hell and back. My apologies. Still, here it goes.

The Motherboard

The motherboard in your computer has “highways” or “lanes of traffic” on which information travels. It helps to picture a highway going right through the middle of town with 16, 32, 64, or 128 lanes. The more lanes you have, the more traffic you can accommodate. Specifically:

• A 16-bit motherboard has 16 lanes of traffic. We refer to these as really old computers.
• 32-bit motherboards have 32 lanes of traffic. We refer to these as microcomputers or personal computers.
• 64-bit motherboards have 64 lanes of traffic.  We have commonly referred to these as mini-computers, such as the IBM AS/400, or Digital VAX system. But you will also find 64-bit computers in children’s video games such as Nintendo 64. Further, many file server class microcomputers today actually have 64-bit motherboards.
• 128-bit motherboards have 128 lanes of traffic. We commonly refer to computers with 128-bit motherboards as mainframe computers.

Here is a picture of a motherboard, not that it tells us anything. I just thought you might like to see one. You cannot actually see the lanes of traffic as they are embedded within the plastic panel. But if you could see them, they would look like little silver highways.

Speed

OK, lets talk mathematics for a minute. You might think that a 32-bit motherboard is twice as fast as a 16-bit motherboard. This is wrong. A 32-bit motherboard is theoretically 8 times faster than a 16-bit motherboard. 64-bit motherboards are theoretically 8 times faster than a 32-bit motherboard, and so on. This is because data can travel in 8 times as many combinations of lanes through the motherboard. In reality, there are various bottlenecks here and limiting factors there that prevent motherboards from truly operating exponentially faster, but the speed gains are certainly more than double when the number bits are doubled.

Operating System

Next, operating systems must be capable of actually seeing all of the lanes of traffic motherboard and addressing all of those lanes of traffic. In the early nineties, it was possible to purchase a 32-bit computer, and install a 16-bit operating system (such as DOS or early versions of Windows) on that computer. In this case, the system would operate, but the operating system only utilized 16 lanes of traffic. To optimize your computer system, you must have an operating system that is specifically written to address the entire motherboard.

Application

Next, the application must be capable of actually seeing all of the lanes of traffic motherboard and addressing all of those lanes of traffic. Even today it is possible to purchase a 32-bit computer, and install a 32-bit operating system on that computer, and then install a 16-bit application (like an old QuickBooks for DOS version). In this case, the application works, but the application only utilized 16 lanes of traffic. To optimize your computer system, you must have both an operating system and an application that is specifically written to address the entire motherboard.

This will help you understand why applications written for mini-computers or mainframe computers will not run on a 32-bit computer. The application will look for 64 or 128 lanes of traffic, but will only find 32 lanes. The resulting confusion causes the system to fail.