This articles explains what is meant by video bandwidth

Bandwidth: A measure of the display performance of a monitor. Expressed in MHz, bandwidth is the number of dots that can be displayed in a line per second. More strictly, it is the frequency response of the system between points where the signal level falls to a specified percentage of its maximum value (usually 50% or 75%). In principle, the greater the bandwidth, the better the monitor - although the quality of the picture tube is often the limiting factor affecting dissplay performance, and for many standard monitors there s little point in increasing the bandwidth beyond a certain point. Typical bandwidth for monitors are as follows:

• VGA monitors: 18 MHz
• FGA+ monitors: 35 MHz
• CAD monitors: 100 MHz