Everything in the digital world is measured in bits and bytes. Bits are a measurement of different components and functions depending on what is being referenced. Following are the most common. See binary values.|
The size of the computer's internal registers. This is the computer's "word" size, which is the amount of data the CPU can compute at the same time. Theoretically, if the clock rates were the same (800 MHz, 1 GHz, 2 GHz, etc.) and the basic architectures were equal, a 32-bit computer would work twice as fast internally as a 16-bit computer. In practice, 8-bit, 16-bit, 32-bit and 64-bit architectures are rarely identical to each other even from the same manufacturer. Thus, a 64-bit computer may be (internally) less than twice as fast or more than twice as fast as a 32-bit computer.
In order to take advantage of a CPU with larger words, operating systems and applications must be recompiled with a compiler that supports the larger word size. If not, the older software may actually run slower in the bigger CPU, but this is totally dependent on the mix of instructions used in the program.
Most important, this measurement does not result in twice as much actual work being done for the user, as the computer's cache size and bus and disk speeds are all part of the performance equation.
The size of the computer's system bus (frontside bus), which is the pathway over which data are transferred between memory and the CPU and between memory and the peripheral devices. If the bus clock rates are equal, a 32-bit bus transfers data twice as fast as a 16-bit bus.
The size of the address bus, which determines how much memory the CPU can address directly. Each bit doubles the number, for example, 20 bits addresses 1 megabyte (MB); 24 bits addresses 16 megabytes (MB); 32 bits addresses 4 gigabytes (GB). See binary values.
The number of colors that can be displayed at one time. This is called "bit depth," "color depth" and "pixel depth." Unless some of the memory is used for cursor or sprite movement, an 8-bit display adapter generates 256 colors; 16-bit, 64K colors; 24-bit, 16.8 million colors. See alpha channel and bit depth.
Bit specifications, such as 64-bit and 128-bit, refer to the display adapter's architecture, which affects speed, not the number of colors. See 64-bit graphics accelerator and 128-bit graphics accelerator.
The quality of sound based on the number of bits in the samples taken. A 16-bit sample yields a number with 65,536 increments compared to 256 in an 8-bit sample. See 8-bit sample and 16-bit sample.