Bob Myers help please: flatscreen 'refresh'

Weaver

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Apr 29, 2004
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Hi Bob - I've got the Dell UltraSharp 2001FP and hoping to bump up the
'refresh rate' to 75/85Hz from 60Hz

Can you predict what might happen please if I force say 85Hz refresh
rate - my risk of course! - to see if I can enable vsync

With vsync enabled and no triple-buffering, low framerate is 60/4Hz
sometimes and I'd prefer 85/4Hz of course :)

16ms response time so looks like 1000/16ms or 62.5Hz - but as an
experiment I'd like to try 85Hz (I believe I had 75Hz once) but not
before checking in to ask you first!

Thanks Bob it won't be the first time you've helped me out :)

Peter
 
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"Weaver" <dratI@forgot.com> wrote in message
news:i9tr81t0hds5iq75v08pql4ae9m4jgk7vq@4ax.com...
> Hi Bob - I've got the Dell UltraSharp 2001FP and hoping to bump up the
> 'refresh rate' to 75/85Hz from 60Hz
>
> Can you predict what might happen please if I force say 85Hz refresh
> rate - my risk of course! - to see if I can enable vsync

Since I'm not familiar with the specifics of this monitor, my
first question would be - is the proposed timing within the range of
what the specs say it will accept? If not, then I wouldn't bother
trying this.

If it is, then what you're probably going to get is a decent image
(maybe a little less sharp or stable if you're using an analog
interface), but you may see some motion artifacts if the monitor
uses frame-rate conversion for this timing. (I.e., the LCD panel
itself is still operating at or near 60 Hz, and the incoming video
is frame-rate-converted to match.) This may offset any
improvement you might see in getting your graphics frame rate
up. (The artifacts which result from FRC come from the
occasional need to drop or double an incoming frame, which has
an effect on the perceived smoothness of motion.)

> With vsync enabled and no triple-buffering, low framerate is 60/4Hz
> sometimes and I'd prefer 85/4Hz of course :)

I'm assuming that you mean the reported graphics-rendering
framerate here; 60/4 being 15 FPS, and 85/4 being 21.25 FPS.
I guess you're the only one who can judge if that change is
significant to you. However, please keep in mind that it's more
important that the rendering frame rate be the fastest you can
*maintain*, not just that you push the peak up as high as possible.
Rendering which occasionally hits a higher peak but in the meantime
varies all over the place will generally not look as nice as it would
if the rate were moderate but steady (and in a decent relationship
with the displayed frame rate).


> 16ms response time so looks like 1000/16ms or 62.5Hz - but as an
> experiment I'd like to try 85Hz (I believe I had 75Hz once) but not
> before checking in to ask you first!

The relationship between response time and the input video
timing isn't really quite that simple. If you're doing this thinking
that you'll improve a flicker situation or so such, I wouldn't bother -
there will not be any actual improvement in that regard.

Bob M.