Planar 20" LCD

[RussSchultz]

I just got a Planar 20" LCD. Its very nice. 1600x1200 native resolution. 25ms response time, etc. etc. blah blah blah.

I bought it, hoping work would reimburse me (1600x1200 is dandy for code development). Alas, they didn't. So now I've got one at home.

Of course, now I need to get a video card that can push 1600x1200 without problems... (I don't think my 9500 non-pro will cut the mustard)

 

[pascal]

Some 9700 for $200

 

[RussSchultz]

Maybe. I'll hold out and see for a few months--the monitor scales 1024x768 quite well.

 

[Nite_Hawk]

I've got a samsung 191t that I use with a 9700pro which does very well. It's native is only 1280x1024 though, so your mileage would likely vary. Still, the 9700pros can be had for a relatively low price right now, so it's something to consider. I suppose the other question is what kind of games do you want to play? 1600x1200 is going to be rough for newer titles coming out if you want to have all the nice eye candy on.

Atleast your display should do 800x600 without any stretching. That's better than most consoles atleast!

Nite_Hawk

 

[epicstruggle]

I just got a Planar 20" LCD. Its very nice. 1600x1200 native resolution.

:drool: damn it, got drool on my keyboard. so do you have any ghosting issues?

later,

 

[RussSchultz]

I've been using a samsung 15" for about 2 years now, so I really don't notice it, even when playing games.

There definately is a different "look" to it, but it doesn't bother me.

 

[fbg1]

I've been looking at 19/20/21" LCD's too, and have noticed something about the resolution. Most of the 20"+ LCD's seem to have 1600x1200 native, but at only 60Hz verticle refresh rate. On CRT's a refresh rate like that creates noticeable screen flicker. You need at least 75Hz, preferably 80Hz+ till the flicker goes away. How about on LCD's?

 

[Dave H]

LCDs don't flicker: unlike a CRT, the entire screen doesn't get redrawn every refresh, only those pixels that change. However, with a low refresh rate you will get ghosting of fast moving objects, and bluriness when the scene changes quickly. As such, LCD's are excellent for handling things like GUIs and word processing/text editing, and not so great at displaying video or games.

 

[BRiT]

Actually, it's the response time that determines how much ghosting appears. With 25ms or less, there is no ghosting. The Planar LCDs typically have 16ms response times.

I use my Dell Ultrasharp 18" LCD with 25ms response time for gaming. I notice no ghosting.

 

[jvd]

the 9500 should drive that screen at 1600x1200. Just don't turn on any fsaa and aniso haha

 

[fbg1]

Thanks for the info Dave and BRiT

 

[Nite_Hawk]

Actually, it's the response time that determines how much ghosting appears. With 25ms or less, there is no ghosting. The Planar LCDs typically have 16ms response times.

I use my Dell Ultrasharp 18" LCD with 25ms response time for gaming. I notice no ghosting.

This isn't actually entirely accurate either. 25ms is generally given as a combined number of how long it takes to go from white to black to white again. Often times, screens with 25ms response times will have much longer response times for situations other than white to black or black to white. The reason for this, is that going from black to white or white to black is easy. You either min or max the voltage to the cells and don't need to stabalize on an intermediate voltage. a 25ms display could very easily take upwards of 50-60ms to go from a light grey to a dark. The result is that some LCDs (such as my 25ms samsung 191t) will have problems with ghosting when showing certain shades of colors.

16ms displays have the same problem. They don't suffer it quite as badly it seems, but there are currently only two 16ms panels currently being manufactured, and each is only 17" in size (several different brand names all use the same panels). Not until feed-forward technology comes out will panels get around this limitation. I've posted about feed-forward tech in a couple other threads here, but the basic idea is that you don't spend nearly as much time stabilizing on a specific voltage to a cell, but instead min or max it, and cut it to the right voltage at exactly the right time, so that it takes dramatically less time to stabalize.

Nite_Hawk

 

[JohnH]

I'd have thought that means you need to introduce a delay on the update so that you can see where the pixel needs to get to in advance. Would be fine for a TV but not necessarily for a computer display. Or maybe I'm thinking about something else.

John.

 

[Nite_Hawk]

John: In both cases (atleast with a digital signal) the monitor is going to receive a color value for a specific pixel. At this point, it's up to the monitor to find a way to quickly make that pixel the right color.

Regular displays set the voltage of the cell to the right value, approach it, and deaccelarate until the voltage is stabalized. Think of it like traveling in a car at 60mph, braking more and more heavily, until you get to a point where instead you start letting up on the brake more and more until you eventually hit 30mph. It's a very smooth transition, but the acceleration and deacceleration of braking takes a long time.

Feed-foward displays instead will set the voltage to either the minimum value, or the maximum value, but only for a certain length of time. This would be like traveling 60mph, slamming on the brakes for the exactly correct length of time so that when you let off, you are travelling at 30mph. It eliminates the extra time the acceleration and deacceleration takes.

Nite_Hawk

 

[JohnH]

Ok, wasn't sure if that alone gave sufficiently small a response time, and that to get it down do acceptable video rates you needed to treat the intensity of each cell as some kind of continuous function. This requires you to know where the pixel is going next or maybe even where its going over the next few "frames" in order to get it to hit the required levels at the required times.

Of course we may be talking about two completly different technologies ;-)

John.

 

[MfA]

This isn't actually entirely accurate either. 25ms is generally given as a combined number of how long it takes to go from white to black to white again. Often times, screens with 25ms response times will have much longer response times for situations other than white to black or black to white. The reason for this, is that going from black to white or white to black is easy. You either min or max the voltage to the cells and don't need to stabalize on an intermediate voltage. a 25ms display could very easily take upwards of 50-60ms to go from a light grey to a dark. The result is that some LCDs (such as my 25ms samsung 191t) will have problems with ghosting when showing certain shades of colors.

Heh I thought for a moment this might be more of a chemical than an electrical issue. I was just thinking that if this was truely caused by nonlinear effects in the transistor (cant be RC delay times, that is not how they work) then this would be "easily" solved with either a sense-line and oversteering or if the response is stable enough just oversteering.

Didnt want to question you without first just googling a bit ... sure enough you are right. So was I, my obvious solution indeed could solve this problem. I am going to bet this obvious idea is patented to such an extent there is no way of implementing it anymore by anyone without a license ... it is just too obvious not to be.

 

[JohnH]

The presence of a frame memory implies a frame of lag, but guess thats generally acceptable. I'd got into my head that it might require more than that, probably halucinating curly wires for some reason..

 

[Nite_Hawk]

MFA:

Here's another article at extremetech that has some useful info and charts:

http://www.extremetech.com/article2/0,3973,10085,00.asp

Nite_Hawk

 

[MfA]

I understand how it works Once you realise what the problem is the solution flows naturally from that.

Actually, you could make a driver which could do exactly this on existing LCD screens ... using a webcam to calibrate itself

On second thought, calibration would be a bitch ... I would have to think about it longer to see if there was a good way of measuring the response time with a webcam.