Cost and Picture Area
There is a direct link between the size of the picture tube and the cost of the monitor. The CRT is the most expensive part of the monitor. GUI operating systems have increased the demand for big screens, to allow for more working area so that the user can have more applications open at once, or more working room for graphics.
Bandwidth
When referring to computer monitors, the term bandwidth is used to denote the greatest number of times an electron gun can be turned on and off in one second. Bandwidth is a key design factor, because it determines the maximum vertical refresh rate of a monitor. It is measured in MHz. Higher numbers are better. The lower the resolution, the faster the bandwidth. When comparing products, remember to measure bandwidth at the same resolution for each product.
Interlacing
Interlacing refreshes the monitor by painting alternate rows on the screen and then coming back and sweeping the sets of rows that were skipped the first time around. This increases the effective refresh rate, but can lead to eyestrain. Interlacing is found on less expensive monitors, and should be avoided unless achieving the very lowest initial cost is the client's key concern.
Power-Saving Features
Because they are the highest consumers of electrical current in the average PC, most new monitors provide some level of power-saving technology. Consequently, VESA has established a standard set of power economy controls to reduce power use when the monitor is idle. These are collectively referred to as Display Power-Management Signaling (DPMS) modes.
DPMS technology uses monitors to gauge activity levels of the display. If there is no change in the data stream from the adapter, as set in either the BIOS or operating system controls, the monitor is switched to inactive status. The goal is to reduce power consumption, while minimizing the amount of time required to restore the display to full intensity when needed. The following table lists DPMS stages, arranged in the order ranging from most to least power used.
| Monitor Status | Video Signal Sent | Monitor Activity Level | Amount of Power Saved | Recovery Time to Normal Display |
|---|---|---|---|---|
| On | Yes | Active | None | N/A |
| Standby | No | Inactive | Fair | Minimal |
| Suspend | Yes | Inactive | Good | Long |
| Off | No | Inactive | Excellent | Longest (Virtually the same as full power) |
Frequently turning a monitor on and off places stress on the components. DPMS reduces the need to use the mechanical switch to turn the device on or off. Clients without power-saving systems in place should be advised to turn on the display only when it is first needed, and to turn it off at the end of each workday.
DPMS can be configured in one of three ways: using hardware, software, or a combination of both. When configuring a system for a new monitor, check the manufacturers' manuals for recommendations on appropriate settings and setup instructions.
