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Dell 2405 FP - 60 or 75 Hertz refresh rate?

Originally posted by: FreshPrince
currently running 1920x1200x32@60Hertz

think if 75Hertz would make it better or not?

any suggestions?
Click to expand...

Try it and post back! 😉

 
Originally posted by: goku
Originally posted by: vi_edit
That's an LCD right? LCD's don't really make use of refresh rates.
Click to expand...

then why is it that at lower resolutions they can run at higher refesh rates?
Click to expand...

I'd say it was more a function of the video card/video card driver than the LCD. You can run an LCD all the way down to 40hz and not notice a difference.

Do that on a CRT and it'll mess with your eyes.
 
Originally posted by: vi_edit
Originally posted by: goku
Originally posted by: vi_edit
That's an LCD right? LCD's don't really make use of refresh rates.
Click to expand...

then why is it that at lower resolutions they can run at higher refesh rates?
Click to expand...

I'd say it was more a function of the video card/video card driver than the LCD. You can run an LCD all the way down to 40hz and not notice a difference.

Do that on a CRT and it'll mess with your eyes.
Click to expand...

Anything lower than 85Hz gives me a headache 😱
 
The source of the light from a TFT display is a CCFL or MCLED (if you happen to be on an un named ship! 😉 ). The CCFL source is basically a CW source as the inverters operate in the tens of kHz range. This is why a 60Hz refresh rate presents no perceivable flicker but is noticed immediately on a CRT.

Running a LCD at a higher refresh rate has no real benefit unless you have a specific need (VSYNC = ON) and desire a higher frame rate.

Cheers!
 
Originally posted by: vi_edit
That's an LCD right? LCD's don't really make use of refresh rates.
Click to expand...

Sure they do.

Originally posted by: FreshPrince
currently running 1920x1200x32@60Hertz

think if 75Hertz would make it better or not?

any suggestions?
Click to expand...

Will make what better? Screen updating frequency? Yeah... Crystal speed? No. Hey...that sounded like a drug.
 
Originally posted by: goku
Originally posted by: vi_edit
That's an LCD right? LCD's don't really make use of refresh rates.
Click to expand...

then why is it that at lower resolutions they can run at higher refesh rates?
Click to expand...

DVI has a specific amount of bandwidth available. if you have it transfer more frames, then those frames have to be smaller.

no, i don't actually know what i'm talking about, but it makes sense to me.
 
LCDs don't refresh. All the pixels are lit (or not) all the time, there is no scanning beam that causes visible flicker if it doesn't come by every spot often enough.

Now, update rate. 60 Hz is plenty enough for today's panels, giving a 16ms period between updates. No panel is ACTUALLY faster than that, marketing hype aside.
 
FreshPrince, you got this thing on DVI or VGA?

On my 9600 with DVI, things are perfect at 60. I can't change it and I don't want to.

However, on my 9200 with VGA, things are a bit fuzzy at 60, but much sharper at 75. Analog doesn't always sync up correctly, at least at first.
 
Originally posted by: Peter
LCDs don't refresh. All the pixels are lit (or not) all the time, there is no scanning beam that causes visible flicker if it doesn't come by every spot often enough.

Now, update rate. 60 Hz is plenty enough for today's panels, giving a 16ms period between updates. No panel is ACTUALLY faster than that, marketing hype aside.
Click to expand...

The thing is you can't equate the refresh rate and the response time.
16ms is how much it takes one pixel to go from 0->255->0 (Tr+Tf) in ANSI standards. Refresh rate is how OFTEN the whole screen is drawn.

I'm not playing devil's advocate here, you can definitely tell the difference between 60 Hz and 75 Hz on an LCD when you move your mouse. The motion is quite a bit smoother as 75 Hz. You may notice more "ghosting" at 75 Hz since the crystals are being requested to change more often, but probably not that bad.

The reciprocal (1/Vrr) of the vertical refresh rate * 1000 will give you how long it takes the CRT to paint the frame. For 60Hz it would be 16.66ms and for 75Hz it would be 13.33ms.

Originally posted by: ElFenix
DVI has a specific amount of bandwidth available. if you have it transfer more frames, then those frames have to be smaller.

no, i don't actually know what i'm talking about, but it makes sense to me.
Click to expand...

Heheh, what you said was a very good way of saying it. The OP does indeed have enough bandwidth to run this mode though.

1680w*1050h*60Hz=105.84 MHz
1680w*1050h*75Hz=132.30 MHz
Single-link DVI (assuming full compliance by GPU's TMDS): ~165 MHz
 
Originally posted by: sm8000
FreshPrince, you got this thing on DVI or VGA?

On my 9600 with DVI, things are perect at 60. I can't change it and I don't want to.

However, on my 9200 with VGA, things are a bit fuzzy at 60, but much sharper at 75. Analog doesn't always sync up correctly, at least at first.
Click to expand...

dvi
 
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