Hardware Reference
In-Depth Information
Beyond the basics, here are some other factors to consider:
Interface(s)
Displays may provide one or several interfaces. A few inexpensive mod-
els provide only a DB-15 analog (VGA) connector. Most displays provide
both a DB-15 and a
Digital Visual Interface
(DVI) connector, which may be
analog-only (DVI-A), digital-only (DVI-D), or hybrid analog/digital (DVI-I).
Some displays provide a
High-Definition Multimedia Interface
(HDMI),
which is compatible with DVI-D but also includes the audio signal on the
same connector. If your video adapter has a DVI-D or DVI-I connector and
your display has an HDMI connector, or vice versa, you can purchase an
adapter cable that will allow the two to function together.
If you intend to watch copy-protected content (such as Blu-ray movies)
on your display, make sure at least one of the DVI or HDMI connectors
includes
High-bandwidth Digital Content Protection
(HDCP) support.
Brightness and contrast
A bright display is important, particularly if your viewing environment
is well lit, and also to give you some reserve as the display backlight-
ing gradually dims with usage. Brightness is specified in
nits
(candellas/
square meter, or cd/m
2
). The least-expensive displays may be rated at only
200 nits. Better displays are generally rated at 250 to 300 nits, and a few
high-end or specialty displays may be rated at 400 nits or more. We con-
sider a display rated at 250 nits or more to be sufficient.
Contrast specifies the ratio between the luminances of the brightest
white and darkest black the monitor can display, and is determined by
panel type and quality as well as backlight intensity. A monitor with high
contrast can display very dark shadows and very bright highlights simul-
taneously and shows gradation in both the shadows and the highlights.
Inexpensive displays have contrast ratios as small as 300:1, and some
high-end or specialty displays are rated as high as 10,000,000:1.
Unfortunately, contrast specifications are essentially useless. Different
display makers use different methods to calculate them. Two comparable
displays from different makers may have identical actual contrasts, and yet
one manufacturer may rate its display at 500:1 and the other at 1,000:1. As
far as we know, each manufacturer is consistent. For example, if one ASUS
display is rated at 500:1 and another at 1,000:1, it's safe to assume that the
latter display has superior contrast.
Response time
Fast response time is important to avoid smearing and other artifacts dur-
ing fast-motion video segments, particularly with 3D computer games.
Typical displays have 4 millisecond (ms) or 5 ms response times, which are
sufficient for anything other than extreme gaming. Premium models and
those targeted at gamers typically have 2 ms to 3 ms response times, with
a few models at less than 2 ms. Inexpensive displays and very large dis-
plays may have slower response times, typically 6 ms to 10 ms, but some-
times 20 ms or more. For general use, we consider a response time of 10
