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Monitors

Description: The monitor displays the output of the video card, showing you the results of calculations that the PC has made. Using either a conventional cathode ray tube (CRT) similar to that used by a television set, or a liquid crystal display (LCD) such as those used on notebook PCs, dots called pixels are set to different colors and brightness levels to display text and graphics.

Tip: For additional information on monitors, including more discussion of many of the technical details, criteria and features mentioned below, see the Reference Guide section on monitors.

Role and Subsystems: The monitor is part of the video subsystem and is closely related to the video card. Despite being located outside the main system box, the monitor is still a vitally important PC component, because its quality has such a big impact on the overall usability of the PC and the comfort level of its user.

Related Components: The monitor and video card; they are partners in many ways and should be purchased to match each others' capabilities.

Key Compatibility Selection Criteria: For the most part, virtually any monitor can be used with virtually any PC; they are amongst the most interchangeable of key components. The most important selection criteria are based on the type of monitor you buy and also on physical size.

The first decision to make is whether you want a conventional CRT monitor or one of the newer LCD types. Many people find that LCD screens produce a sharper, higher-quality picture. They don't flicker the way CRTs sometimes do; they also use much less power and take much less space than CRTs. However, they are also much more expensive than traditional monitors, especially if you are looking for a larger size. Most LCDs are 15" in viewable size; in contrast, CRTs of 20" or larger viewable size are available.

If you decide to go with a CRT, virtually any video card will work with it, and you are likely to have few compatibility problems regarding the video interface. With LCDs, you must make a further choice: whether you want an analog or digital interface to the monitor. Digital LCDs theoretically have better picture quality, but require a special digital video card--regular video cards produce an analog output.

With CRTs, an important issue is physical size and weight. CRTs take a lot of space, and their depth especially can be an issue if you are using them on a smaller desk or table. Some CRT monitors with slightly less depth than regular monitors of that particular size are now available; these are sold as "short neck" units. Very large monitors (20" and up) can be very heavy, weighing 50 pounds or more. Be careful putting these on top of small desktop PC cases, or you may damage your system.

Finally, a CRT's refresh and resolution capabilities must be matched to those of the video card. If the video card puts out its data at a resolution and refresh rate higher than the monitor can handle, the monitor will either shut down, show a scrambled image or (with some cheaper units) may even be damaged. Conversely, having a CRT that supports very high resolution and refresh rates doesn't help if the video card can't take advantage of them. (You might use the extra capability the next time you upgrade your video, however. Monitors are one place where planning for the future can make sense.)

Performance and Capacity Selection Criteria: Most of the emphasis with monitors is on quality issues. The monitor has no impact on performance and so performance criteria do not exist. However, a couple of capacity issues are of relevance: size and resolution support.

Most monitors are given a size measurement which refers to the length across the diagonal of the screen. Nominal sizes for monitors range from 14" to 22" for regular sizes and even higher for very expensive "presentation" or "boardroom" models. More important than nominal size however is viewable image size, which describes the real size of the image on the screen (nominal size includes parts of the CRT that are hidden by the edges of the monitor cabinet.) Be sure to check nominal size, as there can be a difference of up to an inch in size between different models that claim the same nominal CRT size.

Of course, most people like larger monitors, and a main reason is that they let you show either more information or the same information larger. However, larger isn't always better. Some people actually find larger monitors harder on the eyes than smaller monitors are. Larger monitors also cost more than small ones, which means to get a larger monitor of the same quality as a smaller one, you must pay more--sometimes substantially more.

The maximum resolution of the monitor is also important, but only to some extent. Manufacturers typically try to make their monitors support as high a resolution as they possibly can, but sometimes the maximum resolution is only possible by sacrificing sharpness or refresh rate (see below). For example, the last time I shopped for a 17" monitor I found some units capable of running 1280x1024 resolution, while others could only handle 1024x768. The higher resolution would have been a selling point--except that the image at that resolution was so fuzzy, and the text and graphics so hard to read, that I couldn't consider using it anyway. For those monitors the official maximum resolution was 1280x1024, but for me, 1024x768 was the highest practical resolution.

Quality Selection Criteria: Monitor quality is very important, since your eyes are at stake here, especially if you use the monitor a great deal. I could easily write pages and pages about monitor quality, but don't really want to. :^) So I am going to mention some of the key areas and also the ways image quality can be measured, but I'm going to be as brief as I can. Note that the quality criteria mentioned here are primarily oriented around CRT monitors; for more information on LCD screens see the page on notebook-specific component issues.

Note: To properly assess the quality of a monitor model, be sure to see it in person. Make sure the monitor is warmed up, and set to the highest resolution you plan to use on a regular basis. Check both the center of the screen and the four corners for each attribute. If a particular unit seems very bad, ask if they have another of the same model; it might just be a bum unit.

Here are the quality issues to look for:

• Overall Impression: It may be subjective, but it's also the most important, bottom-line consideration: how does the monitor look to you? In the end, your opinion is the only one that matters, and people usually disagree on what looks good and what does not in a monitor. I wouldn't buy a monitor solely based on it looking good subjectively, but I would eliminate a monitor that immediately looked bad to me.
• Refresh Rate: Check the monitor's specifications to find out if it can handle acceptably high refresh rates from the video card for the resolutions you plan to use. You want to aim for at least 72 Hz; 85 Hz or higher is better, though over 100 Hz makes no real difference for most users. (For more, see the discussion of refresh rate under video cards.)
• Flatness: Some CRT screens curve more than others. The flatness of the front screen of the CRT is considered more important to some buyers than it is to others. It can help reduce glare and distortion, and may make the picture easier to view.
• Dot Pitch: This refers to the distance between adjacent sets of red, green and blue dots on the surface of the monitor, and is an essential quality specification. Better monitors have a dot pitch of 0.25 mm or less, and the smaller the better. Cheap monitors may have a dot pitch as high as 0.40 mm, creating blurry, unsharp images at any but very low resolution settings.
• Picture Quality Attributes: There are many different aspects involved in objectively assessing the quality of the picture produced by a monitor. It would take pages to describe them all in detail, so I will list here the most important ones and a very brief description of them:
  • Sharpness: How well-focused and sharp is the monitor?
  • Purity: How accurately does the monitor display areas that are entirely of one color, or entirely white?
  • Geometric Accuracy: Draw lines and circles using a graphics program; are the lines straight or curved? Are the circles uniformly round or ovals?
  • Convergence: Look at white lines on a black background; are they white or tinted one of the primary colors? If the latter, the monitor is showing poor convergence of its colors.
  • Brightness And Contrast: Use the brightness and contrast controls to adjust the monitor. Make sure you can make it both sufficiently bright and dim to match your work environment requirements.
  • Glare: Monitors vary widely in their ability to suppress glare (from windows or artificial lighting.) Check the monitor carefully; a flashlight is helpful if you remember to bring one along.
  • Moir� Patterns: These sometimes appear as wavy contours on screens at certain resolutions and are to be avoided.
• Horizontal "Trinitron Lines": Traditional monitor design creates dots using something called a shadow mask, a sheet with millions of fine holes in it in a specific pattern. These holes let the dots of light shine through onto the CRT screen to create the picture. A different design, popularized by Sony's Trinitron, instead uses an aperture grill, a set of vertical wires through which the electron beam travels. This design creates a brighter image, or so many people believe, but in order to keep these fine wires from vibrating, horizontal stabilizing wires must be run across the surface of the screen. These produce very thin horizontal lines where the image is slightly darker than elsewhere on the screen. Usually two or three lines are produced, depending on the size of the monitor. It is most noticeable when looking at a white screen.
  Some people find these lines and think there is a problem with their CRT; it's actually just the way the aperture grill design works. Sensitivity to these lines is in fact a very personal matter: some people hate them so much that they will not use these monitors; others specifically look for them because they are a "signature" of the Trinitron design, which they consider superior; still others don't even notice the lines. Choose according to your preference.
• Controls: Better monitors have more complete controls, allowing you to change the size, position and shape of the screen image. If a monitor doesn't have these adjustments, then you may have problems if the screen image is "off" somehow. The exact nature of the controls (arrangements of buttons and so forth) varies by model. On-screen displays of monitor settings are now common.
• Failure Rate: An important quality consideration of course is the monitor's history of working reliably. Check out the failure rate of the model you are considering. Avoid models (or manufacturers) with a bad history of problems, or of service in general.
• Energy Use: Newer and better monitors use less power than older and cheaper ones, and may have more power-saving options.

Important Features: Some monitors come with additional features that some find valuable:

• Advanced Controls: Certain monitors come with extra settings, such as color temperature matching, that go beyond the usual collection of image adjustments. These are most useful for those doing serious graphics work.
• Speakers: Some monitors have integrated speakers. These are usually not a great idea, as they are rarely of very good quality, but you may find some that suit you.
• USB Hub: As a convenience, some monitors come with USB ports. You can chain these to the USB controller on the back of your PC to save having to reach around to the USB ports coming from the motherboard.

"Magic Numbers" To Watch For: Nominal image size; always look at viewable image size instead, and don't choose size over quality. Sometimes the dot pitch is also mentioned, but that's a valid, important spec.

Performance Impact: None.

Retail, OEM and Gray Market Issues: Most monitors are sold retail-packaged. Major PC makers label monitors that have been made by others, so OEM monitors are definitely around, and so are gray market monitors. Be very careful with warranty issues on OEM or gray market units!

Importance of Manufacturer: High. There are many reputable monitor manufacturers; choose one of them. Don't buy an el-cheapo monitor from a no-name company.

Typical Component Lifetime: Most PC components can be counted on to keep working for a decade easily, but often become obsolete within a year or two. Monitors are often the exact opposite: they are one of the more failure-prone PC devices, especially CRTs. However, if the model is of good quality there's a good chance it can be moved from one system to another.

Due to these reasons--low obsolescence and high failure when buying low quality--the monitor is not a good place to try to save a few dollars.

Warranty Issues: CRTs fail most often within the first thirty days, but probably fail years after purchase more often than most other components. I would therefore consider a full warranty to be very important for monitors; at least one year, and preferably two or three.

Driver Support Issues: Not really applicable. Just be sure that you have Windows set to the right monitor model type to be sure that the video card does not try to use a refresh setting beyond what the monitor can handle.

Special Specification Considerations: Keep the following additional points in mind when shopping for monitors:

• Many PCs, especially retail ones, do not come with an included monitor. Unfortunately, when the monitor does come with the PC package, it is often of inferior quality. In some cases it is the cheapest monitor the company could find to sell with the unit. Get the specifications and test out the monitor in advance. Do not buy bundled monitors if they are lousy.
• Shop in person if at all possible. If buying sight unseen, be sure you have an unconditional return guarantee at a minimum.
• Always test the monitor using text or graphics most similar to how you plan to use the system. Looking at textual Windows applications on the monitor isn't going to help you decide how good the monitor is for photo or graphics work, for example.

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