Aliasing with PC games?

[texasdoc_2002]

I have a solid ATI video card (9700 I think) with 64 of dedicated memory. A lot of times when I play a game, the screen will be sharp, but then when I pass the ball or something, it will be sort of blurry, and then sharp again when standing still. This is giving me a headache.

Does anyone know the deal with this and how to fix it? Thanks.

 

[jcdenton]

Do you have an LCD flat screen or a regular CRT monitor?

If it's an LCD you might just have one with a poor response time. Not much you can do about that.

If it's a CRT, you might check your refresh rate settings. Actually, IMO everyone should check their refresh settings since so many people leave it at the default of 60 hz, which sucks complete *** (should be at least 75 hz for a flicker-free monitor).

Although it's also worth mentioning that you will need to set your video card refresh rate settings for 3D accelerated games (should be in your display settings for your video card), in addition to your Windows refresh rate setting.

 

[texasdoc_2002]

It is LCD, but I bought one with a fast refresh rate, 60 Hz (16 msec). Someone told me it might be my video card trying to do "anti-aliasing", which I have no idea how to fix.

 

[jcdenton]

I doubt it has anything to do with anti-aliasing since that has nothing to do with movement (there's just as much anti-aliasing happening when the image is still as when it's moving, and it should improve image quality, not make it worse).

If you want to be sure, just go into your display properties and look around until you find the anti-aliasing settings but it should be off by default. It's possible it's another setting causing the problem but I'm not too familiar with ATI cards.

Actually, what is your specific LCD model? You mentioned a 60 hz refresh rate, but I'm pretty sure response time is different than refresh rate. You might have an LCD with a 60 hz refresh rate but poor response time... Or, it's possible that it has a good response time on paper (full on to full off) but poor "gray to gray" response time, which would cause blurriness.

 

[texasdoc_2002]

Here is the link to the monitor.
The Link

Not sure if this helps.

 

[jcdenton]

Well that looks like a good one. Of course even the best LCD's are going to have *some* ghosting vs CRT's so it's possible your eyes are just really sensitive to the effect. Only way to know for sure is if you have a CRT you can hook up to compare.

 

[Do I Make You Horny?]

Wow, nice specs on that monitor and great reviews on that site. Let us know if the problem is with your card or monitor (or what not).

 

[TexasOwnzYou]

what are your in game AA settings set to?

 

[dustin_c1]

jcdenton is right. This is not a problem with anti-aliasing. The effect you are seeing is called "ghosting" and it is fairly common for LCD monitors. Ghosting is caused by a slow response time of the pixels that make up the monitor (i.e. the pixels are not changing color fast enough). A pixel is told to change to one color, and before it completely changes color, it is told to change to another color, and so on and so on. When exagerated it looks like the previous frame's image is still somewhat burned into the monitor for a split second. When it's just a small problem, the image just doesn't look very sharp.

The response times listed by manufactures are all meaningless. Some monitors with supposedly fast response times have problems with ghosting while others with slow response times don't. Some monitors have fast response times in some situations and slow response times in other situations. There isn't a standard for how response times are measured. You monitor says it has a 16ms response time but that doesn't mean jack.


AFAIK, there isn't anything you can do about this other than to buy another monitor or take this one back.

Actually after thinking a little bit more, if you can limit the game's maximum framerate to 30 fps, that might help. The animation will still be smooth and you'll give each pixel a little longer to fully change color before it is directed to change color again.


(also note that when there isn't a lot of motion or rapid color changes you don't notice the ghosting. When a pixel changes from one shade of green to a very near shade of green, not only is the pixel capable of doing it faster than it is if it had to change to a very different color, even if it doesn't change fast, sublte changes in tonality aren't very noticable. But when there is a lot of motion, the pixels are changing to very different colors very rapidly. That's why you see it when there is a lot of action and you don't notice it when there isn't.)

Anti-aliasing blends pixels with certain nearby pixels so that at any given resolution, the final image will appear less pixelated. AA doesn't cause an image to look bad - though some AA filters are better than otheres. The only time AA can be a problem is if your computer isn't powerful enough to run AA filters. When that is the case you see a drop in framerate, not a decrease in image quality.

 

[texasdoc_2002]

What I don't get is that everyone who reviewed this monitor mentioned how there was almost zero "ghosting" with games which are much more graphics intensive than what I am playing (FIFA 2005).

There is an option to turn down the "detail" level on the game, and perhaps I should give that a try.