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Old 01-13-2010, 05:41 PM
Paul E Condon
 
Default Undefined video mode number: 314 --- OT question

On 20100113_115748, Stephen Powell wrote:
> On 2010-01-13 at 07:18:51 -0500, Stanis??aw T. Findeisen wrote:
> > What are those sync frequency ranges?
>
> The sync frequency ranges that the X server assumes for a
> non-EDID monitor when nothing is specified for them

--- snip all the interesting stuff about monitors and video cards ---

> card and monitor combination. Congratulations.
> I don't know about you, but my eyes cannot detect any noticeable
----------------------
> flicker at a 75 Hz vertical refresh rate.
>

Flicker and perception of flicker interest me as a scientific problem:
Is the maximum perceived flicker frequency a property of the optic
nerves in the retina, or is it the result of some frequency filtering
or data averaging in the nerves of the visual cortex?

If it is a feature/function of the visual cortex then one might
expect that there could be fatigue of the visual system from
the activity of removal even though there is no conscious knowledge
that flicker was there in the raw input signal. OTOH, if the raw
signal simply has a upper-half-power frequency in the range of a
few tens of hertz, then there should be no excess mental activity
and no fatigue.

Conventional wisdom is that if you can't see it, it can't harm you
--- but I wonder.

A different way of putting my question is: Is it really your eyes that
cannot detect, or is it that you mind that cannot perceive the
flicker?

Any thoughts on this? Seems like there could be an experimental study
of this issue. Has it been done?

--
Paul E Condon
pecondon@mesanetworks.net


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Old 01-13-2010, 06:00 PM
Stephen Powell
 
Default Undefined video mode number: 314 --- OT question

On 2010-01-13 at 13:41:16 -0500, Paul E Condon wrote:
> A different way of putting my question is: Is it really your eyes that
> cannot detect, or is it that you mind that cannot perceive the
> flicker?

That's a good question. I wish I had a good answer to go with it.
Obviously, higher is better. But if he wants a higher vertical
refresh rate, he's either going to have to use a more capable video
card or else live with lower resolution. That's the bottom line.


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Old 01-13-2010, 06:11 PM
Stan Hoeppner
 
Default Undefined video mode number: 314 --- OT question

Stephen Powell put forth on 1/13/2010 1:00 PM:
> On 2010-01-13 at 13:41:16 -0500, Paul E Condon wrote:
>> A different way of putting my question is: Is it really your eyes that
>> cannot detect, or is it that you mind that cannot perceive the
>> flicker?
>
> That's a good question. I wish I had a good answer to go with it.
> Obviously, higher is better. But if he wants a higher vertical
> refresh rate, he's either going to have to use a more capable video
> card or else live with lower resolution. That's the bottom line.

Or he can do what the rest of the world is doing and buy a flat panel LCD
monitor, where no such thing as a vertical refresh rate exists, nor flicker, nor
eye fatigue. Thus, he could keep his S3 card, running at the highest res and
color depth it will do at 60 Hz, which is the default input signal most DB15 VGA
port equipped LCD monitors expect to see.

I've used nothing but DVI and HDMI with LCDs, so I'm unsure, but, it may be
possible for him to run his S3 at a lower vertical Hz, like 56 or something, to
wring the maximum res and color depth out of his S3 card. I'm guessing from the
situation that a new LCD probably isn't in the cards.

--
Stan


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Old 01-13-2010, 06:43 PM
Stephen Powell
 
Default Undefined video mode number: 314 --- OT question

On 2010-01-13 at 14:11:50 -0500, Stan Hoeppner wrote:
> Or he can do what the rest of the world is doing and buy a flat panel LCD
> monitor, where no such thing as a vertical refresh rate exists, nor flicker, nor
> eye fatigue. Thus, he could keep his S3 card, running at the highest res and
> color depth it will do at 60 Hz, which is the default input signal most DB15 VGA
> port equipped LCD monitors expect to see.
>
> I've used nothing but DVI and HDMI with LCDs, so I'm unsure, but, it may be
> possible for him to run his S3 at a lower vertical Hz, like 56 or something, to
> wring the maximum res and color depth out of his S3 card. I'm guessing from the
> situation that a new LCD probably isn't in the cards.

Yes, that would be an option too. And you're right: the vertical refresh rate
becomes a moot point on LCD displays. But given his existing hardware, his
system is currently optimized about as much as it can be. I've been using a
CRT monitor for years at 75 Hz vertical refresh and never had a problem with
eye fatigue. If it were me, I'd be perfectly content.


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