- — 08 February, 2008 09:30
- The PC processor
- Intel processors
- AMD processors
- Dual processors and multi-core processors -- a dual-core CPU
- The motherboard
- Motherboards for AMD and Intel
- Graphics controller
- Hard drive
- PC case
- Sound cards
- Speaker systems
- Media centre PCs
When PC manufacturers want to shave the dollars off the price of a PC, the monitor is one area that is often addressed. Customers generally choose a system based on hardware specifications such as processor speed and graphics card type, paying little attention to the monitor other than to note its size. This is a short-sighted approach. Since you interact with your screen more than any other part of your computer, you will soon regret any decision to opt for a poor quality display. Monitor technology does not move on as quickly as that of other PC components, so the screen is unlikely to become obsolete.
The most common type of monitor these days is the LCD. Gone are the days of the heavy and bulky CRT monitor, although CRTs can still be found on eBay or other second-hand stores with dirt-cheap price tags attached.
CRTs are big because they use a vacuum tube, illuminating phosphors and electron beams to draw the images onto the screen left-to-right, top-to-bottom. Whereas LCDs are thin because they simply use a set number of switching transistors, backed by a fluorescent or LED array of source light, to create the images that you see on your screen.
The technology used in flat panel displays is quite complex. A liquid crystal solution is held between two sheets of polarising material. An electric current is then passed through the liquid, which makes the crystals align and act as shutters, either allowing light to pass through or blocking it. TFT (thin film transistor) is the technology used in conjunction with LCD to generate colours for flat panel displays.
LCD monitors consume less electricity than comparably sized CRT monitors and they are much easier to physically install and manoeuvre. Furthermore, some LCD screens can also be pivoted to display their output in a portrait orientation, rather than landscape, which is perfect when working on long documents.
What sizes do CRT monitors come in?
The most common size over the last 12-18 months has been 19in, but 22in widescreen displays are also very popular. You can buy a decent 19in LCD screen for around $350, while 22in widescreen displays start from around $450. Larger screens are also available. Sizes of 24in, 26in and 27in are not uncommon and these are often equipped with plenty of connectivity options, allowing them to be connected to set-top boxes, DVD or Blu-ray and HD-DVD players as well as computers.
The resolution of the monitor -- which also acts as a gauge for the amount of detail a display offers -- comes from the number of pixels (short for "picture elements") and lines.
LCD monitors all have a native resolution at which they look best and they can't go any higher. For example, a 19in monitor will have a native resolution of 1280x1024 pixels, while a 22in widescreen monitor will have a native resolution of 1680x1050 pixels.
These resolutions represent the physical amount of pixels that are available on the screen so lower resolutions do not scale well. Using a lower-than-native resolution will make the image look muddy and less defined. Likewise, higher-than-native resolutions can't be used. The native resolution of LCD monitors is one of the reasons many gamers did not take to LCD monitors early on. It meant that games would have to be played at a specific resolution, which often would be higher than the resolution at which the graphics card could produce playable frame rates, although some gamers with high-end graphics cards had the opposite problem: they wanted to play at much higher resolutions.
You may have seen a reference in LCD monitor specifications to a term called response time and wondered what it was all about. Response time refers to the amount of time it takes for the crystals in the panel to move from an on to off state.
With the higher a response time, the greater the blurring effect on bright moving images on black backgrounds. The lower the response time, the less of a blurring effect there will be on the screen. Gamers and graphics professionals used to shy away from LCDs for this reason alone but as of late, monitor manufacturers are releasing models with response times as low as 1 or 2 milliseconds (ms). This can be a misleading statistic though as some vendors claim the time it takes for a pixel to switch from black to white, while others claim the time it takes to switch from grey to grey. Grey to grey times specify the time it take for the screen to switch from one shade of grey to another, while black to white response time measures the time it takes for the screen to change from black to white (rise) and back to black (fall).
Theses two types of response times are not comparable and grey to grey time will be lower. Furthermore, the grey to grey specification is not standardised, so the same response time between monitors could still produce different results. It's best to view the monitor in the store, if you can, to see if you can pick up on any blurring.
Generally, a response time of 8ms (grey to grey) should be fine for playing games and watching movies without blurring.
It's important not to confuse response time with refresh rate. The two are very different things. The refresh rate refers to the number of times the screen image is refreshed per second and, luckily, it's not something that you need to worry about for an LCD monitor.
Other things to look out for apart from the size and response time of an LCD monitor, there are a few other things you need to be aware of.
Viewable angle: this refers to how well you'll be able to view the monitor from the sides and from the top and bottom. A monitor with wide viewing angles is preferred -- anything over 170 degrees should be okay, anything less than that might cause too much colour shift and contrast change in the image.
Colours: in order to produce fast response times, some monitors used panels that can only display around 16 million colours. Monitors such as these use algorithms to make up colours that aren't in their spectrum and could therefore be prone to dithering or colour stepping. It's best to buy a monitor that has a colour rating of 16.7 million colours, especially if you will be working with photographs.
Dot pitch: the dot pitch refers to how closely spaced the pixels are on a screen. A smaller number will produce cleaner curves and lines. It's a specification that should be taken into account on larger monitors, in particular, where relatively small resolutions are used. For example, a 27in monitor with a 1920x1200 resolution will have a larger dot pitch than a 24in with the same resolution. As such, some 'jaggedness' might be visible when viewing the 27in screen from relatively close-up.
Ports: Nearly all LCD monitors will come with an analogue D-Sub port and a digital DVI port. Using DVI, your graphics card -- if it has a DVI port (and if you buy a new PC today, it should) -- won't have to convert the output to an analogue signal and then back to digital. Some monitors also ship with an HDMI port, which can transport digital video and audio over the same cable and it's the preferred connection for watching high-definition video content. Component, S-Video and composite are other types of ports you might be able to find, but not on mid-range or entry-level monitors.
HDCP: high-definition copy protection is implemented in many Blu-ray and HD-DVD movies. If you plan to watch these types of movies on your PC, then you'll need an LCD monitor that has an HDCP-capable DVI or HDMI port, otherwise you will only be able to watch high-definition content at a lower resolution using the analogue D-Sub port. Note that your graphics card will also have to be HDCP-capable.