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CompTIA A+ Certification All-in-One Exam Guide

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game.

Refresh Rate The refresh rate for an LCD monitor refers to how often a

screen can change or update completely. Think of the refresh rate as a

metronome or timer and you’ll be closer to how it works in an LCD. For

most computing issues, 60 Hz is fine and that’s been the standard for the

industry. Humans see things that change as infrequently as 24 times per

second—the standard for motion pictures at the cinema—as motion, not a

series of flickering pictures. To be able to change almost three times faster

makes the movement smoother with less lag, important in applications such

as fast-moving games. Common higher-end monitors today, though, go well

beyond, offering refresh rates of 144, 165, and 240 Hz.

NOTE Higher-end video cards can push well beyond the limits of even the

best monitor refresh rates. See the discussion on “Adaptive Sync” later in this

chapter for the scoop.

Contrast Ratio Old CRT monitors lingered in a few professions for a long

time because early LCDs just couldn’t produce the color saturation or

richness of contrast of a CRT. It was not unusual, even in the late 2000s, to

walk into a design studio and see a few working CRTs.

LCD technology continues to improve every year, and manufacturers

today can produce panels that rival the old CRT technology. A good contrast

ratio—the difference between the darkest and lightest spots that the monitor

can display—is 450:1, although a quick trip to a computer store will reveal

LCDs with lower levels (250:1) and higher levels (1000:1).

LCD monitor manufacturers market a dynamic contrast ratio number for

their monitors, which measures the difference between a full-on, all-white

screen, and a full-off, or all-black screen. This yields a much higher number

than the standard contrast ratio. My Samsung panels have a 1000:1 contrast

ratio, for example, but a 20,000:1 dynamic contrast ratio. Sounds awesome,

right? In general, the dynamic contrast ratio doesn’t affect viewing on

computer monitors. Focus on the standard contrast ratio when making

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