One of the most common questions we get asked is whether it is worth spending more money on a higher resolution projector, and it's a good question, as it can affect the price you pay for your projector by hundreds of pounds.

As you'd expect, the answer is slightly technical, but hopefully this explanation will help turn it into English.

What is SVGA, XGA and SXGA?

These are the main standards of resolution. The resolution is the number of 'pixels' that the projector is capable of displaying. Pixels are the individual dots that make up the image on your computer.

SVGA, XGA and SXGA are terms that describe common resolutions used by computers and projectors.The table below shows you the number of pixels that are displayed in each common resolution.

How does this apply to projectors?

Every projector has a 'native' resolution (sometimes called 'true resolution'). That's the maximum number of pixels it can actually project individually. So an SVGA projector can only display 480,000 pixels at a time.

This may sound like a lot, but if you take a typical projection screen of 2 metres width, each pixel is going to be a quarter of a centimetre wide, whereas with an XGA projector the image is going to be under a fifth of a centimetre wide, and over 60% more pixels are displayed. This means the image is going to be sharper and less 'blocky' when projecting with an XGA projector.

So does the resolution just affect how sharp my image is?

No. It also affects the compatibility of your projector with your computer. If your computer is sending a signal to the projector that is XGA, and your projector has SVGA resolution, this causes a bit of a problem. Most projectors have compression technology, so you'll still see an image, but there are serious downsides with this (see the section on XGA and SXGA compression below for details).

You should also consider the longer-term investment you are making in a projector. Most computers sold today run in XGA resolution as standard, and SVGA is used less commonly. If you start using computers that run using XGA as standard in the future, you may find you are limited with an SVGA projector.

How do I find out what resolution my computer is using?

On a PC, go to Control Panel and select 'Display'. Then, click on the last tab, called 'Settings'. In the bottom right corner of this box is a setting called 'Screen Area'.If this reads '800 x 600' you are running in SVGA mode. If it reads '1024 x 768' you are running in XGA mode.If it reads '1280 x 1024' you are running in SXGA mode.

(Mac users: On an Apple Macintosh, go to the 'Monitors' section of your Control Settings. Depending on what type of Mac you are using, you will find a similar setting to that described above.)

If you are running SXGA mode, you will probably find that the price of buying an SXGA projector outweighs the benefit of running your presentations in this resolution. In this case you need to change the resolution setting of your computer when using your projector.

Can't I just change my resolution setting and buy an SVGA projector?

Yes you can, but the payoff is that you will lose sharpness and will have the inconvenience of having to make sure your computer is always in SVGA mode for presentations.

My computer uses SVGA. Is XGA still better for me?

Yes. An XGA projector will handle an SVGA image without distortion, so you don't lose anything but you do get more flexibility to use different resolutions, and your projector is more future proof. However, for many customers these benefits will not be sufficient to justify the extra expense of buying an XGA projector.

What is 'XGA compression' and 'SXGA compression'?

Most projectors will accept a resolution higher than their native resolution, but will 'compress' the computer's image into fewer pixels. The result is that some of the computer's pixels are 'shared' across the same pixel that the projector displays.This is less important with photos and video, because you don't notice it so much, but with text it's a different story – especially small text, as illustrated by the picture below.

This picture simulates how an SVGA projector displays text in an XGA image using two different kinds of compression. The second example is more common in most projectors. Some manufacturers have better compression technology (such as NEC) that displays text more like the top image. (NB: This text has been enlarged to illustrate this point).

Still got questions?

No problem. Just call or email us and ask us any questions you have about resolution, or any other technical aspect of projectors. We're here to help and advise you if and when you need us.