When people look for things like this, it’s because they don’t realize that you don’t need 0 ms monitors. Most of the ones out there won’t give you any different experience from any others, and it’s very rare that you’ll find one that you could notice and difference at all.
Okay delay happens because of image post processing.
This is additional image processing that happens with the processor located in your LCD HDTV or Monitor.
On some big screen HDTVs this is to give you the best picture you can get for movie watching, it also gets you horrible input lag for game play.
On all LCD screens you do have the following
Scalling - Ether up scalling or down scalling to make the picture fit the screen. So in a 1080p Display, a 480p image has to get resized to fill all of a 1080p screen.
Aspect correction - Ether adding black bars/borders, zooming in and cropping the image or to stretching or squashing the image to make the pictures dimensions fir the screen. This is common with 4:3 images on a 16:9 screen or a 16:9 image on a 4:3 screen. In the past 16:9 is considered widescreen format.
Deinterlacing - LCD screens can only display a Progressive image, interlaced video goes to some kind of process to turn the image to progressive. I cover interlacing in a bit.
Interlacing: Half of the screen is displayed at a time. Every other scan line is skipped when a picture is scanned in each frame, for one frame its all the even number frames and the next frame all the odd number frames.
A Interlaced picture is still a 60 hz, 60 FPS picture. The reason to go interlace on CRT screens was to save on bandwidth on the radio air waves and on analog video games. Newer analog and digital connection formats are given enough bandwidth for a progressive 60 hz picture. On some CRT screens you will notice these scan lines on older video games, they will appear as black lines going the width of the screen.
The reason some CRT screens can go as high as 1080i is that the nature how a CRT screen works the image can only scan in Interlaced format.
Why older games has scan lines, old game consoles up to the Sega Saturn and PS1 (there are Saturn and PS1 games that are in 240p and/or 480i and rarely 480p) might have scan lines as the console actually outputs the image not 480i but as 240p. The analog nature of CRT screens will scan in the 240p image as 480i as treating each 240p scan line as a even number scan line, leaving the odd number scan lines as blank in the effect stretching the image and creating the visual artifact we call scan lines. 240p is a non-standard format and exist as a cheat for older game consoles so they don’t have to push out a larger image.
There is no such thing as a display with 0 lag. If you take a reading at the bottom of a CRT of the time it takes to draw a frame it will be 17 ms, so all screens always have at least 17 ms of time to draw a frame. Anything more than 17 ms is the lag. If the reading from a meter is 27 ms at the bottom of the screen, then the lag would be 10 ms.
This is not strictly true, just because you’re updating at 60hz does not mean the monitor requires 1/60th of a second to finish scanning lines. There’s actually no reason you can’t run something like SFV PC on a screen at 144hz. Or even 200hz if you still have a good CRT knocking about. You won’t get more than 60 frames per second but the time the monitor takes to finish drawing scanlines will be lower.
Taking 17ms to reach the bottom of the screen is a 60hz limitation that consoles don’t really have any say in, but these days on PC it’s not a problem to be running a 60hz game engine on a screen at a higher refresh rate. At 120hz you’re not taking 17ms to reach the bottom of the screen, you’re taking 8ms.
OK fair enough a TFT is still slower because of other delays, but 17ms isn’t a hard limit for a CRT.