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Now, this is where the performance hit comes in. Let's say you bumped your resolution up to 800x600x24bpp. Now instead of your computer only having to keep track of 307,200 pixels (640 X 480) with 256 colors for each pixel, it now has to keep track of 480,000 pixels (800 X 600) with 16.7 million colors available to each pixel.

Another performance hit you will take is the vertical refresh rate. This is mainly dependent upon the graphics card manufacturer and varies among models. The inside of your computer monitor is coated with a material called phosphor. When light hits it, it makes the phosphor glow. Well, it only glows for a little while, so it must be hit with light again to keep it glowing. The refresh rate (in Hz) is how many times the whole screen is updated per second (light hits the phosphor on the screen). Some common ones are 60Hz, 72Hz, 75Hz, 100Hz. The faster (higher) the refresh rate, the less noticeable the screen flicker is.

Screen flicker is very apparent to some people, and not to others. For example, I cannot set my refresh rate below 70Hz, because I can see the flicker staring directly at the screen, and I've heard of some people who can see 75Hz refresh rates. Here's a test for you. Look at something close to your monitor, but only so that you can see your monitor screen in your peripheral vision. See the flickering?

This is extremely apparent when you are watching TV and you can see a computer screen in the shot. See that massive flicker? That is because television is recorded at 30fps (frames per second), and the monitor is refreshing at some rate, let's say 65Hz. You're going to see flicker. If the rates were reversed (i.e. the tape runs at 65fps, and the monitor has a refresh rate of 30Hz, you would be able to watch each line being refreshed instead of flicker).

The Analogy The Change
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