Lcd madness...

[Nowhere]

NOTE to Nowhere: DO NOT edit this post anymore

He is marbeled by this monitor so much, that he will tell me all day that it can work at 75 Hz (that's what he sees in windows...); he just doesn't understand that because the monitor does analog->digital convertion (and because how lcds work in general...) it always has basically the same resolution/frequency (is it 60Hz, or am I wrong? besides, whatever; one thing I'm sure: the screen doesn't work physically at 75 Hz, and I doubt it can at 70...) no matter what you throw at it...
Of course he points me to manual where the frequency ranges are stated...and he doesn't listen apparently when I tell him that it just means what signals the monitor is able to receive from graphics card...

So could you please point me to the most credible source possible where it will be stated how lcd's work in general? (mostly about "fixed" parameters even in case of lcd with analog-in)...
Thanks for help

[agallag]

From http://www.ges.com.sg/refresh.html

Does refresh rate matter for LCD monitors?

LCD monitors are very different creatures from conventional CRT monitors. They are digital devices whereas CRT monitors are analog. Refresh rates are really only relevant for CRT monitors. The higher the refresh rate, the better the display quality on the CRT.

LCD monitors will support a specified range of refresh rates. As long as the refresh rate is set within this range, the monitor will display properly. Otherwise, the display may flicker. With LCD monitors, a higher refresh rate does not mean a better display.

[Wombat]

Faster refresh rates on LCD don't do much except burn them out quicker. It probably IS updating the information for the screen that fast, but the only advantage he might be getting is in frames/second.

[rylan]

Yeah, the info from agallag is correct. I work with LCDs a lot (design medical lcd panels at work), and there are ranges that they can work in depending on the A/D interface board in the panel. Generally there is a range of frequencies that the panel will accept, with 60Hz being the standard 'mininum' frequency, and many analog capture inputs accepting up to 75 or even 85Hz. However, the analog to digital board generates its own syncs for the lcd driver array based on the specs for the glass. The vast majority of glass out there has sync specs for 60Hz refresh with 65Hz max, even though you can 'overdrive' the circuitry to get higher refresh and it'll still work. The analog capture portion usually has a line buffer controler and generates the appropriate timings to get 60Hz refresh to the glass regardless of the input timings, as long as they are within the acceptable range. Its not just the refresh rate that determines if you can display an image properly... you also need appropriate Hsync and front/back porch windows for analog capture, and all of that can be tweaked by the conversion board to still get 60Hz to the panel. So your original assumption is correct, that the majority of LCDs are somewhat 'fixed' parameters for operating frequency. There is a range, but its usually fairly narrow for refresh rate, and 60Hz is normally what the glass actually does.

[az]

Originally posted by Wombat
Faster refresh rates on LCD don't do much except burn them out quicker. It probably IS updating the information for the screen that fast, but the only advantage he might be getting is in frames/second.

Not even that. LCDs are much slower in changing from black to white or vice versa than CRTs, and for true 60 Hz, you'd need the screen to be able to change the state of a pixel within (1/60th second = )16.<span style="overline">6</span> milliseconds. Only now are TFTs coming out which allegedly do switch within 16 ms, however tests reveal that they in practice need a little longer.

So the faster refresh rate won't give you anything because the panel can't draw it.

AZ

[Paulr]

When I was running my LCD on analogue I was able to select refresh rates of 70hz & 75hz when running 1280x1024.
To begin with, especially if you are coming from a CRT, it is extremely tempting to switch your refresh rate as high as possible.
Once you switch to a true digital signal and start using DVI then a lot of LCD's actually stop you using 70hz & 75hz, they only let you go as high as 60hz.
It's not until you start using the LCD that it eventually dawns on you that refresh rate does not matter and really should be taken out of the specification for panels - Response Rate & Contrast Ratio are two features far more important to an LCD.

The only time the 60hz refresh rate of an LCD could be a problem is if you were running VSync:On as that is of course going to limit FPS to 60.
With my 9700Pro, NEC 1760NX 16ms LCD combination I never run VSync on, so those refresh rates certainly don't effect me.

[UtwigMU]

I'd say some LCD people go in line with emperor's new clothing:
- Look at the colours.
- No, it doesn't ghost (or the ghosting is tolerable).

etc...

[az]

Paulr, you have the 1760NX! Fantastic! I'm considering buying this screen (once I have enough money ), or the 1860NX - is it good? Aren't things a little small on the 17"? Should I consider getting the 18", since it costs only 100 EUR more, and has an IPS panel (instead of TN)?

AZ

[The PIT]

The larger models has a total time of 30ms. 15 up and 15 down so I presume it would ghost.

[rylan]

btw response time isn't the only thing that causes 'ghosting'... its also image retention, which is an artifact with the crystals holding charge after the transistor switched it off.. az, if the resolution is the same I'd go with IPS. I can't stand the narrow viewing angle and color inversion of TN for color desktop displays. Response time is a little slower on IPS though, so I'd check the specs. You'll still have some ghosting and blur with high speed movement either way though... you don't start to reduce that until using VA technology.

[VJ]

Anybody seen this display:
bottom of this list: http://www.pc.ibm.com/us/accessories...allmodels.html

http://www-132.ibm.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=-840&langId=-1&partNumber=9503DG3&storeId=1

3840x2400...
(where is that drool icon that ZokesPro proposed ?)


Jörg

[GNEP]

I think that there was a thread about it a while back - iirc it comes supplied with one of the MMS cards to drive it...

[CHHAS]

In the lastest test I saw of it, it was delivered with a special nVidia card, I'll see if I can dig it up.

[Paulr]

I absolutely adore my 1760NX.
Over the years I've made a lot of PC based purchases and on each occasion I've been pleased with what I've bought.
However I can, in all honesty, say that this LCD is the best purchase I've ever made.
The image is sharp, the colours are outstanding.
The ghosting (in my eyes) is non-existant even on the fastest of games.
Once I'd added the DVI cable things just sharpened up a little more and I feel I'm looking at a perfect display.
I feel that the NEC also has one of the nicest overall designs - the usual display people go for is the Hitachi 16ms model and I just feel it's plain damn ugly compared to the NEC - the UK height adjustable stand with the NEC is also another great feature.
The NEC is certainly not the cheapest LCD, I paid £335+vat plus I had to buy a DVI cable as NEC don't ship one with it.
First time I switched it on there was a single lazy pixel in the top-right corner (I could see blue on a black screen).
However after 5-10 minutes of use and looping 3DMark03 on it this vanished and has not re-appeared.

The reason I stuck with a 17" display was two fold.
Cost and response time.
Certainly at the time and may still be the case now, displays larger than 17" don't have the super-fast 16ms response time.
I'm sure this will change and sooner rather than later, but I do game (I'm no hardcore gamer though) and I needed the fast response rate.
I moved from a 17" CRT so to me this was a screen size increase.
A 19" CRT owner shouldn't notice any difference whereas a 21" CRT owner is obviously going to get a decrease in screen size.
Cost was the other issue, the low end 18" panels were quoting some pretty terrible response rates, up to 40ms in some cases.
Those that were claiming faster times (think 25ms was the fastest I saw) were a lot more expensive than the one I purchased.

It is a great display, there is no way I could go back to CRT now.
I'm not going to attempt to change anybody's mind in the CRT Vs LCD argument.
In my eyes I've never seen such a clear, sharp and vivid display as the NEC 1760NX - no CRT I've ever seen or used comes close, the CRT I'm stuck on at work seems blurry in comparision.
The argument on ghosting I also feel is non-existant now, I've played plenty of games on this display and I'm yet to see any ghosting at all.
I experienced some streaking if I scroll a Word or IE document really fast and I mean too fast to actually read, so not something I do on a regular basis.
And the difference it makes to your eyes!!
I used to suffer from headaches, my old Iiyama VM Pro410 would display 1280x1024@85hz and after a couple of hours use the head would start to ache.
Honestly since I moved to LCD I've not had a single computer related headache.

It really is just a great display.
As has been said before, LCD's are not for everyone and I urge people to actually see them in operation before spending a lot of money on them - if at all possible see the actual make/model you are going to purchase.
I ignored my own advice, I purchased the NEC blindly when all around me were purchasing the Hitachi - it was a good decision

[az]

Good to hear, thank you Paulr

I also think than the NECs have the most beautiful screens there are (besides LG and Samsung), and since I not only look into the screen all day, but look at it too many hours a day, it's a piece of furniture and thus shouldn't be as ugly as most LCDs still are.

Since I don't game much (and if I do, it's mostly slower titles) I don't need ultra-fast response times.

Aren't fonts a little small on a 17"? (NOTE: My girlfriend will use the screen too, and she runs 1024 on a 17" CRT, and finds this barely acceptable - though 800 would clearly be too little room).

AZ