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Question about LCD monitors

Last response: in Graphics & Displays
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October 16, 2007 3:17:02 PM

I have a question about LCD monitors. It was always my assumption that all LCD monitors had a screen refresh rate of 60 Hz... is that a correct assumption?

Also, if a LCD monitor is only refreshing the screen 60 times per second, is there any need for the graphic card to output more than 60 frames per second?

I usually turn V-sync on --- so my frames per second get capped at 60. Any comments?

More about : question lcd monitors

October 17, 2007 3:28:54 AM

either 60 or 75 i belive is for LCD monitors, that is the usual.
and if you disable vsync, it will go above 60fps.
October 17, 2007 4:09:54 AM

yea, my 19inch lcd is at 75hz.
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a b U Graphics card
a b C Monitor
October 17, 2007 5:38:22 AM

Most if not all lcds update at 60hz. Even if they take a 75hz signal they just drop frames. Additionally most lcds running through a 15 pin dsub (vga) connector look much sharper when set to 60hz.

Running with vsync on is just as smooth as with it off but it can cause latency if double buffering is used (like in most games). In other words you might notice the image lags behind your mouse movements with vsync turned on. Turning it off will only help if your application runs at a very high frame rate (120+ hz).
a b U Graphics card
October 17, 2007 6:22:19 AM

That's why you enable triple buffering. Technically LCDs don't have a refresh rate (as they don't refresh), it is just a compatibility thing with the video card, which is designed to work with CRTs too.
a b U Graphics card
a b C Monitor
October 17, 2007 8:04:03 AM

Never ever triple buffer it delays the frame by upto 1/20th of a second.

Well I suppose if you are watching a demo that is fine.

If something is drawing to a back buffer while you are watching an old frame in the front buffer it means you aren't seeing the most current information. Double buffering is necessary to have a complete image but triple buffering it just a bad idea.

This is the same reason while alternate frame SLI is dubiously useful for twitch gaming.

While LCDs don't scan like a CRT they do have periodic updates to the whole screen which happen every 1/60th of a second. Some LCD panels, particularly overdrive panels (*cough* Samsung *cough*) have a back buffer of their own and delay the frame even more. This is why you should avoid panels that do to much image processing.

I'm pretty sure the 60hz updates are part of the DVI standard, anyway there is talk of 120hz panels. I think some DLP televisions run at 120hz.

October 17, 2007 3:36:28 PM

Thanks all!
!