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Monitor "Refresh Rate" reported by Windows

Discussion in 'Computers, Hardware, and Operating Systems' started by NM7G, May 9, 2012.

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  1. NM7G

    NM7G Ham Member

    I'm trying to solve an apparent eye-strain computer use relationship. Please show me where I'm wrong about this!

    I think, when Windows XP reports (in Control panel/Graphics/Settings/Adv) that 60 Hz is the "optimal refresh rate" (also maximum) for a LG 22" LCD monitor configured for 1920 X 1080 pixels and VGA interface, XP reports what's in the monitor .inf file, and that the particular monitor can't run any faster, by design. The user's guide says Horizontal Sync Frequency is automatic in the 30 - 83 HZ range, and Vertical Freq, is 56 - 75 Hz, also automatically controlled.

    If I'm wrong (I want to be), Windows factors in info about the video card, Northbridge, and maybe the CPU as well.

    I want at least 70 Hz, but don't think I can achieve it with this monitor. Do I need to ditch the monitor, or is there something else that will bump up the refresh rate without buying a new LCD?
     
  2. AF6LJ

    AF6LJ Ham Member

    Windows only takes the information the monitor sends to the computer and the driver information for that video card.


    If you want a faster refreash rate you need to lower the resolution to something like 1280 X 1024.
     
  3. NM7G

    NM7G Ham Member

    Thanks, Sue. So, I'll find another use for this monitor, then start shopping. 73
    Gary
     
  4. KT1F

    KT1F Ham Member

    What problem are you trying to solve?

    I'm no expert but I don't think refresh rate is particularly important for an LCD monitor. I don't think you get the flicker that you get with a CRT screen if the refresh rate is too slow.

    I guess refresh rate for an LCD just means how quickly the image can change. That might matter while watching moving videos but it probably doesn't make much difference in most computer situations.
     
  5. KA9JLM

    KA9JLM Platinum Subscriber

    That would be a better setting for that monitor.

    The eye strain is more likely to happen at the higher screen resolution, and refresh rate on a LCD has little to do with Eye strain.
     
  6. AF6LJ

    AF6LJ Ham Member

    Just change the monitor settings in the control panel.







    WooW look at that...
    Twenty Killoposts
    I need a life :D
     
  7. NM7G

    NM7G Ham Member

    Thanks for all your inputs! I came to this forum knowing I'd get straight talk with best intentions.

    There is a considerable amount of evidence from web searches, that whether you call it "refresh" or flicker speed, or write-rewrite speed, with a LCD monitor faster is better for many eyes. As with CRT displays and TVs, the slower the refresh rate is, the more eyes attempt to track every single minute change in an image. Not everyone's eye muscles are equal. They're some of the tiniest muscles in the body, yet we often work them excessively.

    I forgot to say, I plan to replace the graphics card with a much faster card before I scrap the 22" LG. I want 1920 X 1080. I'm convinced it can be done, one way or another, without excessive eye strain.

    73, Gary
     
  8. K6ABZ

    K6ABZ Ham Member

    In fact, the refresh rate has virtually no effect on LCD monitors.

    The refresh rate actually sets the speed at which the computer redraws the image on the display. In the case of CRT displays, the phosphor on the screen starts to dim very quickly after it's hit with an electron, so higher refresh rates prevent flicker. Also, refresh rates that are NOT 60Hz help prevent interaction with fluorescent lights.

    However, LCD monitors don't work this way. The pixels stay in their current state until they're changed, and so there's no flicker - at any refresh rate. Because of this, LCD monitors don't accept refresh rates of anything other than 60Hz any more.

    If you're having eyestrain problems, the issue could be resolution, brightness, or a need for glasses.

    If the screen appears blurry - even when you're using the native resolution of the display, you could also be using a bad VGA cable. LCD displays do a very good job of showing the defects in cheap video cables, and they really highlight reflections when you use extension cables. Those reflections create a ghost effect on the screen, causing text to "smear" to the right.

    The best quality you're going to get is to use the display's native resolution and use a digital video cable: either HDMI or DVI. Once you've done that, then address issues with lighting and see if that helps.
     
  9. AF6LJ

    AF6LJ Ham Member

    That's the ticket Gary, faster graphics card...
    They are cheap and if you have seventy-five dollars or so to shell out a nice card that will do the job can be had.
     
  10. NM7G

    NM7G Ham Member

    1. I have new glasses, with PC use factored in.
    2. I've placed a black curtain behind my chair to block extraneous light from striking the screen

    I agree that 60Hz seems to be the standard now for new monitors, but that doesn't change human physiology. I believe the many people who say they gained relief with higher refresh, even if it's a placebo effect. The brain is the vision organ anyway. Eyes are input sensors. The brain controls eye muscles, so let's fool it if it works. The term refresh rate may seem archaic, but LCDs have a Response Time, the time it takes to change color of a pixel, then change it back to its original color. If the image I'm viewing has 2M pixels, and 500k of them change color abruptly, isn't that affecting the brain similarly to repainting an electron beam across phosphors on a CRT? It's change.

    It seems likely that 2.07M pixels are a big part of the problem. On my other PC, I do video editing, EZNEC modeling, and a little CAD on a 17" CRT. It doesn't tire my eyes nearly as badly, however, it runs 1024 X 768, a third as many pixels.

    Great inputs folks! I'll see this through to a conclusion and let you know how it turns out.
     
    Last edited: May 9, 2012
  11. KA9JLM

    KA9JLM Platinum Subscriber

    As mentioned, just a refresher, lol

    LCD pixels get turned on by current and turned off when the current stops. On the other hand CRT pixels get excited when the electron beam hits them and immediate start to fade.

    With a too low refresh rate, a CRT appears to flicker as the brain has time to notice that it went dark. This depends on the individual and which part of the eye sees it since our peripheral vision is more sensitive to light.

    An LCD does not appear to flicker because pixels do not go dark between refreshes. They simply transition from one state to the next, and do not need to change on every refresh cycle, unless the screen information for that pixel has changed.

    The refresh rate of both CRTs and LCDs affect how they render motion. Higher refreshes give smoother motion.

    LCDs have an upper limit on the refresh rate due to the time it takes for a pixel to change state. This is known as response time. If the refresh rate is too fast, then some pixels do not have enough time to change and this results in ghosting.

    A CRT with a short persistence phosphorescent screen will flicker big time, but will have no lag.


    A bigger faster LED monitor would be the best solution if you want to run 1920 X 1080, and are worried about Response Rate.

    A 27 inch or bigger would be nice for CAD, and would greatly reduce Eye Strain when running 1920 X 1080.

    The nice thing about a new one, Is that the prices keep dropping, unless you want the very newest.
     
  12. K6ABZ

    K6ABZ Ham Member


    Maybe you could tell us what you're doing with the computer. If you're reading text, the image literally does not change in between screen refreshes. There's nothing there affecting your brain, because the visual image does not change until the frame buffer changes.

    Now you could have an older, junky monitor that can't actually display full 24 bit color. In that case, the monitors "fix" this by flipping the pixels between two different colors in order to display colors that can't be rendered directly. In that case, a new monitor may help. But you're not going to get a higher refresh rate, because the underlying technology actually makes higher refresh rates counterproductive for several reasons. The biggest reason is that higher refresh rates require more bandwidth, and this actually reduces video quality - especially on analog video cables. This also requires your video card to work harder, re-drawing the scene and the frame buffer more often. The solution there is simply to adopt a color scheme that doesn't require interpolating. Saturated primary colors work the best; personally, I use a jet black desktop and a white foreground.

    "The Internet" is more often wrong than right. If people are telling you that setting the refresh rate on their LCD monitors is improving their eyestrain - I'd take that with a huge grain of salt. There are people who say WiFi makes them sick. I know a lady who won't eat food that's touched plastic. I even know someone who believes Neil Armstrong didn't step on the moon.

    Fixing your lighting is the place to start. You want the wall behind your monitor to be the same brightness as your monitor at about 75% illumination. Cutting down your lighting is the wrong thing to do. You want a room that's well lit but not too bright. Imagine that your LCD, when fully lit with a white page, is a piece of paper. Adjust your brightness and your lighting so that the LCD is no brighter than a piece of paper on your desktop.

    If you can afford a bigger monitor, give it a try. If you're using analog video cables, switch to DVI or HDMI.
     
    Last edited: May 9, 2012
  13. NM7G

    NM7G Ham Member

    Many LCD's response times have come down to 2 mS. Progress is good.

    I concluded the same about a bigger, faster monitor. 120Hz refresh rate monitors exist (for 1920 X 1080). They're intended for 3D, but in 2D will still yield 120 Hz, but must have a dual-link DVI interface. Otherwise, they default to 60Hz. I'm not in a rush to pay $600 plus for a Samsung S27A950D. My clunker PC didn't cost nearly that much.
     
  14. WA9SVD

    WA9SVD Ham Member


    Look before you leap! Your video card may be the problem, and can't provide the refresh rate you desire; the problem isn't necessarily the problem
     
  15. KA9JLM

    KA9JLM Platinum Subscriber

    People have been getting sick using the 3D technology.
     
  16. WA9SVD

    WA9SVD Ham Member


    My bad. I MEANT that the problem isn't necessarily with the monitor, the video card may not support higher refresh rates at the resolution you desire. Check both the specs of the monitor AND the video card to see if they will support the resolution and refresh rate you require or desire.
     
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