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I have read many posts about refresh rate but my problem is that I am unable to understand them properly.

I am here to ask what is the refresh rate of a monitor. Is it a helpful parameter? If so what is the best refresh rate for my monitor and how to find it?

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Wikipedia: en.wikipedia.org/wiki/Refresh_rate –  dangowans Sep 3 '12 at 13:59
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-1 "This question does not show any research effort". What don't you understand that wikipedia doesn't already explain? en.wikipedia.org/wiki/Refresh_Rate –  Baarn Sep 3 '12 at 13:59
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that was huge , could you provide some simple description and there is nothing about how to find proper best RR . –  AgentCool Sep 3 '12 at 14:03
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I think given the prevalence of LCD monitors this probably isn't terribly common knowledge like it once was. –  ultrasawblade Sep 3 '12 at 15:55

2 Answers 2

up vote 3 down vote accepted

CRT's generate a picture by painting a phosphor with an electron beam. The picture fades quickly so this has to be done continuously.

It blanks the beam when it reaches the bottom and returns to the top (this is called vertical blank) and also briefly each line when it hits the right edge and returns to the left edge, one line lower. Typically there are some extra unused lines called overscan. Each iteration of a complete screen "paint" including vertical blank and overscan is called a frame.

The number of times it paints a screen (frames) per second is the refresh rate. If the refresh rate is too low, the monitor image will appear to flicker due to the phosphor fading too much before the next repaint. Generally 60 times a second (60Hz) is enough for most users to not notice any flicker. Some users are more comfortable with a higher rate, such as 75Hz.

Some older CRTs without firmware within them could actually be harmed by setting a refresh rate too high. This hasn't been true of monitors for well over 15 years now, though.

The higher the refresh rate, the harder your graphics card or video decoder might have to work to keep up with it, as it needs to have an image ready once per frame for the smoothest motion.

Some types of 3D technology require the refresh rate to be doubled to 120Hz, as basically the graphics card is rendering a separate image for your left and right eye.

LCD monitors work differently - the millions of transistors that make up the screen are manipulated by a microcontroller with RAM and it "holds" the received image once it's been decoded. So there is no fading. Consequently most LCDs are fixed at 60Hz or 120Hz, although a few can lower it to 45Hz or similar (probably for power savings) - but you won't see a flicker like you will with LCDs.

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Thank you very much , very clear explanation . one small question . if i kept as 70Hz or 75 Hz is there any harm to eyes ? –  AgentCool Sep 3 '12 at 16:12
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If anything it's probably going to be easier on your eyes and help prevent eyestrain. I'm no authority on the effects of CRT "radiation" or similar, though. Would make sense for a higher refresh rate to equal more emitted radiation but I'm really not sure. It's probably not a big enough difference to matter. –  ultrasawblade Sep 3 '12 at 18:18

To know what is the refresh rate, I sugggest you reading the wikipedia article.

It is a very helpful parameter, depending on the context, and more importantly if you can be helped by it. However it is totally impossible to answer your question as is.

The best refresh rate for your monitor is dependent on your type and model of monitor, and is usually supplied by your monitor's manufacturer. You can find in on the manual of your monitor.

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