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Does Your LCD Play Catch-Up To Your Mouse?
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?"
Have you hugged your penguin today?
I'd recommend popping in Knoppix and see how it works. It will probably pick an open driver made for your graphics card family. You say this happens with the mouse, what about typing?
I'm not annoyed with my LCD because I informed myself before actually buying one. I got myself a Samsung 712N, which has a response time of 12ms. I havn't noticed any ghosting or lag.
Qui ne va pas à la chasse n'a pas de gibier
PHP Queb
Caveat to the original poster--I know nothing about your Dell LCD display, and haven't looked at your video...
Back in the DirectX 7 era, there were a number of video drivers that would use huge pushbuffers/command buffers so that you could actually have 10 or more frames worth of rendering scenes queued up before they would make it to the screen. (It's one of those naughty driver tricks that helps certain benchmark scores at the expense of actual users). It often was the case that as long as you locked the frame buffer once per frame (as older games did to display UI/overlays) it would force it to actually display in real time, but if you stopped doing that (which was what you were supposed to do for max performance) you could get as much as three seconds behind on some systems!
Anyways, I thought that those problems were behind us, although I haven't been all that up on PC video driver stuff for a few years... However, as the parent to this post says, if the problem was due to the actual LCD response time, it wouldn't look like latency, but instead more like ghosting/smearing. I'd definitely try it on another PC first before blaming the monitor...
Never, under any circumstances base buying decisions off of reviews from Newegg. Half the reviewers state they're first time system builders with no real idea of what there doing. The other half try to sound like they know what they're talking about, but obviously have no clue, or are just flat out lieing. Then you have the problem that newegg removes the reviews that are less than pleasant. Your best bet is to read a site that focuses on reviews and sells no hardware. Maybe Slashdot could start a hardware review section and do some unbiased hard journalism!
--fetch daddy's blue fright wig, i must be handsome when i release my rage
Yes, but the Dell 2001 FP has the lowest response time available in a consumer LCD on the market today (16 ms, which is less than the time one frame is displayed at 60 FPS). So if a 2001 FP can't do it, no LCD can. Besides, LCD ghosting results in a blurry picture, not lag in a clear picture.
main(c,r){for(r=32;r;) printf(++c>31?c=!r--,"\n":c<r?" ":~c&r?" `":" #");}
... and have never, ever, seen this problem - and we do push these screens pretty much as hard as you'd want to (it's an aircraft command and control environment). Using either DVI or analogue signals, coming out of Dell hardware (my employer's preferred supplier).
Might be something 2001-specific, but from the description given, that sounds like an issue I'd peg on something else, not on the display.
i'm getting tired of this so i'll just copypaste a port of the FA.
"
If I scoot the mouse across the screen, there is a noticeable 9 millisecond delay between when I move the mouse and when the cursor moves. 9 milliseconds was a number I pulled out of a hat, but the point is that, yes, there is a definite delay.
As my proof to you, I have video. I have my 2001FP as my main monitor, and my wife's old CRT as the second monitor (it used to be a better setup, but I've had three monitors die on me at home). If I move a window that spans both monitors, you can actually see the lag on the LCD screen. The video card has two outputs, and when I switch it around with the CRT as the main monitor, the lag is still visible (just to get those possible variables out of the way for you).
"
so, it's not sensitivity issue, it's not wireless mouse issue, it's not input issue of any kind, it pretty much can't be a graphics card issue of any kind either.
world was created 5 seconds before this post as it is.
I bought a Samsung SyncMaster 171v two years ago, and brought it home fearfully waiting for the ghosting I had heard about with LCD monitors. No such experience. In my day-to-day work I don't notice any GUI delays that can be blamed on the monitor. And even when playing games (like Enemy Territory) the monitor performs beautifully.
But I have seen other people with LCD monitors that don't seem to work as well with fast moving objects. The SyncMaster wasn't a particularly expensive model or anything, but it definitely performs well.
I'll join the chorus of people saying "no". Either it's a problem somewhere else in your system, or a really crappy LCD.
:-), which has made a complete convert out of me.
... "we're stylish and we're not going to let you forget it!").
I used to not like LCD monitors, especially the kind that use the analogue video out, but at work I got an NEC MultiSync LCD 1760v (17", 1280x1024 -- I know, yesterday's news, but a great step up for me
Not only does it have far better contrast and brightness than other LCD monitors I've used, but it has no ghosting of any kind, and tracks the analogue video output of my computer flawlessly. Even the industrial design is great, much better than typical "we've got a really expensive CAD system and no design sense whatsoever" designs, and I'd say on par with Apple's wonderful creations (without Apple's tendency to be a bit poncy
The display gamma seems to be much different than my old CRT, so it did take a bunch of adjustment to get pictures looking the same.
Anyway, 3 thumbs up for the 1760V from me (this model is a few years old I think).
We live, as we dream -- alone....
I'll bet the monitor in question is connected with a VGA plug. I've never seen that happen with a laptop display, and your Cinema display uses DVI. It's also a Dell, so what can you expect? "Dude, you're going to Hell!"
#naabhaprzrag, #sverubfr-000, #agi-fcbafberq, negvpyr[pynff*=' negvpyr-ary-'] { qvfcynl: abar !vzcbegnag; }
but seriously, did you check your system for spyware. some of them buggers can hog your CPU pretty bad.
If you don't know what AltaVista is (was), get off my lawn.
the original quote is from John Glenn, when he was asked what it felt like sitting atop the rocket, ready to launch:
"I felt about as good as anybody would, sitting in a capsule on top of a rocket that were both built by the lowest bidder." (Senator John Glenn, Colonel USMC, Retired)
Rockhound is applying the sincerest form of flattery.
If you forget about the future, the future will forget about you.
> I've never never seen any kind of lag like this in any kind of monitor.
An idiot that posts that gets a +4? What in the hell? If you don't understand something, don't moderate posts about the topic!
All LCD's have a long (in terms of human response) display update lag. They are terrible. It takes a long time to get the crystals to turn. I'm an IT director for a company that does CG animation, and this is why our animators refuse to use LCD monitors. A few of our guys that work only with static images have expensive SGI LCD's, but even those are terrible at handling motion. This is also why your mouse cursor disappears when in motion when using an LCD display.
Again, moderators, stop giving mod points to idiots!
It's your mouse drivers.
I've got a wireless mouse that has absolutely no lag under Windows - but try playing a DirectX game, and it's got tons of lag. Because I rarely game on that machine, I haven't taken the time to figure it out - but if I plug a regular USB mouse into it, it works just fine.
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
There is no modification twice between sequence points in that code. Note that ',' '?' and ':' are all sequence points.
The code you quoted is exactly identical to:
if (++c > 31)
{
c = !r--;
printf("\n");
}
else if (c r)
printf(" ");
else if (~c & r)
printf(" `");
else
printf(" #");
However the original code has undefined behaviour in other ways:
- invalid definition of main()
- failure to return an int from main()
- calling of variadic function printf() without a prototype
Having said that, running it (and presuming you're on a system where the above UBs don't cause trouble), produces a surprisingly cool effect considering the size of the program.
Why? dunno.. just know I have to do it or the mouse won't work properly.
I'm not anti-social, I'm anti-idiot.
My LCD's (2 identical units) have no lag over DVI or VGA.
With NTSC video, the delay is noticable. Any video with motion will blur (rolling credits, hockey ads around the edge of the ice - not that it's a problem now.) Audio is completely out of sync, and I need an audio delay somewhere to make things line up.
FWIW, the NTSC input is directly into the monitors, not through an external converter.
I use Macs to up my productivity, so up yours Microsoft!
Waffle Iron,
THANK YOU! Excellent post my friend. I just created a small bmp in paint with different sized black squares on a white background, then tiled it for my background -> Autoadjusted my LCD.
It looks fucking fantastic, text is smooth and clear, unbelievable. Thanks a million man, most useful post I've read on slashdot. Note, and this isn't even at my LCD's native resolution (1280x1024, whereas I am running 1280x960). Amazing, didn't think this was possible.
Try watching an action movie with some fast karate type moves on your slow LCD. Blurred in the fastest action spots. This is why LCD oems are starting to release 16ms and 12ms models.
I'll have to say BS on this. My suggestion is to borrow a second CRT and hook it up the same way. Most likely the lag will still be there. I have no idea what OS as the video is down. My answer is to upgrade the video drivers and check for some stupid setting being messed up.
As an EE I'll say that what the article is talking about is possible, but not likely. (It would be stupid to make a display with that much delay.)
It comes down to this, any sort of processing has an inherent delay. If this particular LCD was using a really long pipeline to process the incoming data stream, he could be seing the effects of this.
It's not totally crazy to believe that this is what's going on. There has already been one HDTV manufacturer who has offered to replace circuit boards inside their TVs with new ones that have faster chips due to customer complaints about the delay. Apparently some of the new TVs out there have a pretty significant problem.
See this eariler slashdot article for details.
Life is too short to proofread.
That's my guess. A lot of things happen during the vertical blanking interval or on some other similar periodic interrupt. In most OSes, this includes screen updates and mouse pointer redraws. This could be anything from a buggy driver to an IRQ conflict, or possibly even a bad trace on the motherboard (though the latter isn't anywhere near as likely).
If an OS reinstall doesn't solve the problem, there's probably something weird going on in the BIOS settings and/or the motherboard itself. Pull the BIOS battery for an hour. Try again. If that doesn't work... is your clock running slowly, too? If so, buy a new computer. If not... buy a new computer. EIther way. :-p
<rant>And speaking of IRQ conflicts... why hasn't any motherboard manufacturer broken with tradition and actually added enough distinctly addressable interrupt lines? I mean, the Mac has supported 64+ interrupts on its interrupt controller since 1995. Does it really take a decade of engineering to figure out how to cascade two interrupt controllers and add a driver to support it? Sheesh!</rant>
Sigh. Another victim of a 2004 computer crammed into a 1981 architecture....
120 character sigs suck. Make it 250.
sub-pixel sampling on fonts does not work very good at all unless you use a DVI connector for your LCD.
Funny, the sub-pixel antialiasing looks virtually identical on my laptop, my pair of aging 15 inch LCD panels, and every other LCD I've tried. All except for the laptop(s) are analog.
I changed from a VGA to a DVI connector on my LCD panel at work and the difference is astounding.
If you are seeing that much of a difference you might want to learn how to adjust you LCD. So far, every single time I have seen an LCD look bad it has either been poorly auto-adjusted or is running at the wrong resolution.
It helps some if when you hit the auto-adjust button you have an image with nice sharp edges up on the screen. If it is still not quite clear, you may have to make some (probably minor) adjustments to the phase/clock yourself. If you still have issues you might want to change your refresh rate. My old panels "flicker" quite a bit at 60hz, but look fine at 72hz.
BTW, companies now make excellent DVI/USB KVM switches, so there is no execuse to use a VGA connection on a LCD panel anymore.
Cost is probably a good excuse, especially for the 90% of consumers of which you are speaking. It would be better to educate them on proper configuration of their equipment.
There's a kernel patch which cranks the usb mouse sampling up to 500hz. For high speed aim based games its noticeably smoother. There is also a technique for doing the same thing in XP.
THANK YOU. Awesome trick. I put up the images as you described them. These worked for me. I did notice my LCD acting really weird when these images were being displayed. I don't recommend keeping the image on the monitor for any longer than needed. http://www.hackermedia.net/downloads/lcd-cal
Hacker Media
Yeah. Most of us refuse to consider the possibility because it's utterly stupid.
...
I can imagine that similar things were said when it was suggested that the Earth wasn't at the center of the universe and that everything didn't revolve around it.
Disprove his evidence instead of mocking it as "stupid" and inconceivable.
I've never seen lag like that caused by an LCD and I can't imagine how the electronics could create that effect.
The demonstration video showed the LCD off by 1 or 2 frames. Nobody would notice that kind of delay unless the LCD were placed next to a CRT in a multi-mon configuration. And hey, guess what this guy did?
At 30fps, that delay would be 33 to 66ms. The LCD switching speeds in monitors these days seem to range between 16 to 20ms. So, question is, can you realistically introduce another 13 to 50ms? Don't forget to include the A2D converters and circuitry designed to compensate for mismatching the refresh rate from the preferred rate...
Like another post already said, the LCD would need a screen data buffer of several megabytes and it doesn't have one.
You don't need a large data buffer to see that kind of effect, you just need a long enough data pipeline.
the lag in ms is really a sellingpoint in europe. I got one with 16ms... I had one of those dell screens, and it had something in the range of 45ms... Which means my screen had a higher latancy than my Internetconnection! Sell the screen and buy a new one... Do some research this time... (I bought mine because the price, about 100$ 1½ year ago)
Some ASUS boards, (eg A7V8X-X) support advanced IRQ management - when the board runs out of IRQs, it creates virtual interrupts and assigns them instead :) Very handy, I currently have somewhere between 20-25 IRQs on my system :)
Not to ignore your suggestions, but the computer was the same across 2 setups and only the monitor changed. Therefore, it's probably only the monitor that's a problem. There have been numerable /. articles about cheap displays using crappy DSP's, which caused a significant lag (significant enough to have audio and video out of sync). Could this be the problem?
-=-=-=-=-=
I'd rather be flamed than ignored.
I have used 2 LCD monitors with VGA inputs for the past 3 years and I have never seen lag like that. Something is wrong with his OS/Drivers or maybe some trojan has infected his system(maybe a hidden vnc server is lagging his system :).
Here's an experiment, type a bunch of text in your favorite text editor or play some audio files with a low-impact spectrum analyzer - if both of these sync properly, then you'll know not to blame the monitor. Also, check video drivers, plug another monitor in for testing... Troubleshooting is your friend.
-- In Soviet Russia, radio listens to YOU!
IIRC, the infamous "code to explode a monitor" trick involved setting monitors to refresh rates that the monitor could not handle, causing the monitor to burn out or, in extreme cases, explode. It was a small subset of the monitors, but it was one of those things that made it into popular lore. I belive they even referenced it in Cryptonomicon, having a character who supposed had his face mangled by an exploding monitor triggered by a virus of some sort.
This sig has absolutely no significance and serves only to take up screen space and waste the time of the reader.
IIRC, the interrupt controller ORIGINALLY used in the IBM PC (Programmable Interrupt Controller? I think that was what the part was called) could, in theory, cascade to as many interrupts as your heart desires.
So why did they stop at so few?
Need vs. cost. Most people (i.e. the masses) don't need very many interrupts. They are going to play a few games, check their mail and that pretty much covers it.
So, what do you expect from a low cost platform but low quality specs? Blame the masses and the designers. Much like getting cheap coffee - you get what you pay for.
IANAL, but I've seen actors play them on TV
Most people are just not aware of it and take it for granted. I cannot count how many time I showed my fellow co-workers how confy they get by pushing the refresh right higher (75Hz is great).
Regarding eyes and such. You will more easily get headaches or eye-aches if you keep a low refresh rate. That will also cause your eyes to get tired faster, and they will have to make more efforts to adjust. Your eye muscles will take much of that effort and probably get tired after a while. After a long while, they won't be able to adjust as they used to.
That is part of the reason why I browse at -4.75 with contact lenses since I am 12...