Does Your LCD Play Catch-Up To Your Mouse?

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Does Your LCD Play Catch-Up To Your Mouse?

Posted by timothy on Sunday September 26, 2004 @12:53PM from the it-wants-to-eat-your-pointer dept.

Dishes of Ryan writes "I fell in love with the idea of an LCD monitor, so I ended up buying a nice, shiny Dell 2001FP. However, nowhere, and I mean *nowhere* did I read about LCDs having an input lag on them. For instance, if I scoot the mouse across the screen, there is a noticeable delay between when I move the mouse and when the cursor moves. To prove it to people, made a video showing exactly what I mean. You can almost forget being king of the hill on twitch FPS games like Unreal Tournament. Are there any other Slashdotters out there that are as annoyed as I am? What did you do?"

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Re:Need a different monitor by AKAImBatman · 2004-09-26 13:00 · Score: 5, Informative

I just thought of something you might want to try. LCDs are a bit different than CRTs in that they are completely digital. Since the monitor is digital, it sometimes requires calibration when used with an analog connector. Check your manufacturers specs for the EXACT resolution AND refresh rate that they recommend. The monitor will run in other modes, but it supposedly won't do them as well.

Once you've set your resolution and refresh rate, be sure to use the auto-adjust button if your monitor has it. When I first got mine, I thought the picture looked like crap. Then I found the auto-adjust. With a push of a button, I suddenly saw the crispest text I'd ever seen in my life. Quite an improvement over CRT displays. :-)

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Um, no. by autopr0n · 2004-09-26 13:09 · Score: 5, Informative

I've used lots of LCDs, including plenty of DELL LCDs. The LCDs we've used at work were faded, and the colors looked awful after a copule of years. but I've never never seen any kind of lag like this in any kind of monitor.

My guess is that there is something wrong with the video drivers, or the mouse drivers, or some other part of his computer that's causing these problems.

I can't see the vid because the file is apperantly slashdotted.

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autopr0n is like, down and stuff.
Site and Video Mirror by cybermint · 2004-09-26 13:27 · Score: 5, Informative

Site Mirror: Click here.
Video Only: Click here.
Re:Need a different monitor by Waffle+Iron · 2004-09-26 13:39 · Score: 5, Informative

One thing I noticed is that if you have a screen full of anti-aliased text, the auto adjust may not have enough edges to crunch on. I have a big bitmap of alternating black and white pixels that I put up to test the monitor's synch to the pixel clock.
If I autoadjust while showing normal windows, the bitmap will usually still have fuzzy areas when I pull it up. If I autoadjust while the bitmap is being displayed, the monitor is able to lock onto it perfectly. The text looks noticeably better with a perfect lock, especially when using sub-pixel sampling on the fonts, which needs pixel-perfect alignment to work properly.
I have a shortcut to this image on my systems because I have a KVM switch, so I need to autoadjust a lot. No two systems have the exact same video timings.
Re:post the image? by Waffle+Iron · 2004-09-26 15:14 · Score: 5, Informative

I don't have a site handy, but you can make your own with Windows paint.exe. Just create a black-and-white bitmap, and the color palette is replace with various bit patterns. Floodfill the whole image with the 50% black pattern.
You can probably do the same thing with Gimp, but it's not immediately obvious to me how to do it.
Re:Cursor "Submarining" by timeOday · 2004-09-26 16:19 · Score: 5, Informative

This was a big problem with passive matrix screens.
No, read the article:
Note: This is different than an LCD's response time. Response time measures how quickly an LCD pixel can turn on and off. It's a measurement that is pretty much used to say how much "ghosting" you can expect.
He's talking about fast response time (no ghosting) but noticeable latency between when the signal goes into the monitor and when it starts to be displayed (so he thinks).
To which my question is this: if the monitor is running several frames behind the video card, where are those frames being stored? We're talking about many megabytes of image data here. A single 1600x1200x32bpp frame is over 7 megabytes. The monitor has no buffer that could do such a thing.
To me this points to a cause in the computer rather than the monitor, perhaps in the drivers as others suggested.
Re:Need a different monitor by Venotar · 2004-09-26 17:33 · Score: 5, Informative

Megane said:
> I'll bet the monitor in question is connected
> with a VGA plug

And Zorilla responded:
> That Dell monitor is probably a rebadged Samsung
> or LG.

Megane,

I have one of the Dell 2001FPs connected via a VGA cable (it's on a machine that doesn't get used for much gaming so it's connected to a slightly older video card) and I haven't notice a lag when moving the mouse (although I'm in front of my Hercules right now, so I can't actually test to see if the Dell shows the symptoms displayed in his video).

Zorilla,

You're partially correct. The Dell 2001FP contains a LG.Philips LM201U04 panel. The rest of the monitor is Dell designed; although not Dell built.
how to do it in GIMP by Mr+Z · 2004-09-26 20:33 · Score: 5, Informative
The following sequence seems to do the trick w/ GIMP 1.2.x:
- Create a new greyscale image that's the size of your screen
- Go to "Filters->Render->Patterns->Checkerboard. " Pick a checkerboard size of 1.
That should get you a checkerboard pattern on a 1-pixel increment. I haven't seen what this does for an LCD monitor's ability to fine tune an analog signal (since I don't own such a display), but I think it's the pattern you're using. It's the same fill pattern the old monochrome Macs used for their desktops. LOTS of edges to sync on, on every line! :-)
--Joe
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