Higher refresh rates = fuzzy

[HouRman]

I have a question about refresh rates... Why is it when I lower my refresh rate to 60hz @ 1280x1024, I get a much crisper and cleaner look to windows 98se and XP pro with 2D applications. (Than at 100hz @ 1280x1024)

When I raise the resolution to 1600x1200 @ 85hz (Which is optimal for my monitor), it does not look AS clean and clear as the monitor running at 75hz or 60hz.

Is this due to my graphics card? My card is a Creative Annihiliator Pro Nvidia Geforce 256 ddr which is 2 years old. I've cut the capacitors in hope of improving my 2d but noticed nothing.

I just found out how clear it looks when I reformatted and windows XP put a standard driver on which reduced my refresh rate to 60hz @ 1280 x 1024 which looks awsome. I've never seen anything as crisp on my monitor.

19" P1460 Cornerstone Shadow Mask CRT

My guess is that it's the video card... thanks

 

[EMAN]

It's not because of your video card.

Set your refresh rate to 85hz or until you don't get any eye strain.

 

[Gosharkss]

It could very well be your video card.


Some video card manufacturers put RF filters on the output of the video signal. They do this to reduce Radio frequency interference cause by the pixel clock and video signals on the video card. These filters are designed such that they reduce RF interference as you increase the video rate and do virtually nothing at lower signal rates. As you increase the refresh rate, you are increasing the video rate and the filter circuit starts to take affect. This explains why everything looks sharp at lower refresh rate.

A perfect video signal would have sharp edges with no overshoot or undershoot and the rise and fall time of the signal would happen in zero time. Nothing happens in zero time. The filters on the video lines add capacitance to the lines, thus they slow the rise and fall time of the signal. This slow rise/fall time of the signal essentially stretches the time the signal is on making the image on the screen appear fuzzy or out of focus. It also prevents the signal from reaching a full on (white) state or a full off (black) state at the higher frequencies. This reduces the contrast ratio and makes dark backgrounds or text look gray instead of black.

The design of the DAC can also have a similar affect if its output capacitance is high.

Did you also cut off the inductors and resistors that are in the circuit?

 

[HouRman]

so you're saying i am experiencing eye strain? Right now i'm at 1152x864 @ 91khz / 99hz

My monitor is optimal at 1600x1200 @ 85hz..

So should I be running at optimal because the "clear" screan I'm looking at can be creating eye strain?

 

[HouRman]

Gosharkss, I've almost completely removed the filter from my video card (which I believe makes it not pass fcc regulations) by clipping 9 capacitors off.

Here's what happens with my modified video card:

1600x1200 @ 85hz = fuzzy
1600x1200 @ 75hz = a bit clearer
1600x1200 @ 60hz = clear

thanks

 

[Gosharkss]

The question is, are you having problems with eyestrain. Some people run thier monitors at 60Hz and never experience any problems. Others need to run at 85Hz or above.

If you are running 1152 x 864 at 99Hz, I doubt that there is any perceivable flicker that could lead to eyestrain. If you are happy at this resolution I see no reason to change.

Refresh rate is one thing that can cause eyestrain however in your environment, you are likely to find several things that can cause eyestrain, including glare on walls and reflections on the computer screen itself. Minimizing reflections and reducing ambient light are particularly important aspects of your physical-viewing environment. When your monitor power is off, it may surprise you to find that one of the reflections that you see is your own! In order to minimize reflections of things in front of your screen other than lights - including your own face - it helps to reduce the general light level (ambient illumination). Use window shades, blinds, or drapes to block out excessive sunlight, also reduce the internal ambient light if outside light cannot be reduced. Use proper lighting, overhead fluorescent lights tend to be an excessively bright source of ambient illumination, in addition to facilitating reflections. Reduce the lighting by using fewer light bulbs or florescent tubes or use lower intensity bulbs and tubes. I recommend using indirect lighting with a dimmer control, such as stand up halogen lamps that reflect light off the ceiling.

Once you have your environment set up, reduce the contrast setting of the monitor. Resist the temptation to run your monitor too bright. White should be a pleasant white, it doesn't have to illuminate your room. Operate your monitor only at a comfortable brightness / contrast level. This may also help reduce eyestrain.

 

[yummer]

It is the video card.. as you increase the refresh rate towards the upper limits of the video card's RAMDACs, the signal-to-noise ratio of the video card decreases (might be due to the RF filters on the video card... not sure). The fuzziness you see is entirely dependant on the video card. If you get another video card, your results at the same resolution may be different. If you have a monitor that looks 'crisp' at 60Hz but 'fuzzy' at the same resolution at a higher refresh rate, then the monitor is CAPABLE of the same crisp output at the higher resolution, but the graphics card is the limiting factor.

 

[Kingofcomputer]

could be the vga card, could be the monitor.
the card or the monitor says it can do this rate doesn't mean it can do it well,
especially on cheapy card and monitor.

my diamond s3 virge can do 85Hz, but it's fuzzy at 85Hz, clear at 75Hz, so have to run it at 75Hz even the monitor can do 85Hz clear with other cards.