LCD Monitors

[therowdy via HWKB.com]

I have a new Samsung 940B analog/digital monitors. It has a refresh rate of
8ms but the recommended screen refresh rate is 60hz. I am told that 8ms
monitors should be set to 75hz to obtain the 8ms refresh rate.

Is there a reason why Samsung recommends 60hz rather then the fast capable
speed of 75hz? Loading the Samsung driver actually hides all other then 60hz.

I wrote to Samsung and all they said

8ms is the response time of the LCD panel itself. The total monitor response
time also includes the signal processing time in the circuit.
Increasing the fresh rate to 75Hz does reduce the signal processing time but
it does not show as obvious as the panel itself.
We still recommend 60Hz refresh rate for all LCD Monitors

 

[Mike Ruskai]

I have a new Samsung 940B analog/digital monitors. It has a refresh rate of
8ms but the recommended screen refresh rate is 60hz. I am told that 8ms
monitors should be set to 75hz to obtain the 8ms refresh rate.

8ms is the (advertised) response time, not refresh rate. That means
it takes 8ms for a pixel to change from one color to another. Or
less. It depends on the magnitude of the color change. If it was
advertised as grey-to-grey, then some changes will take more than 8ms.

Strictly speaking, you'd need a 125Hz refresh rate to match an 8ms
response time (1000/8 = 125). But you wouldn't notice the difference,
since LCD's don't flicker like CRT's do, and 60 updates a second is
plenty.

Is there a reason why Samsung recommends 60hz rather then the fast capable
speed of 75hz? Loading the Samsung driver actually hides all other then 60hz.

I wrote to Samsung and all they said

8ms is the response time of the LCD panel itself. The total monitor response
time also includes the signal processing time in the circuit.
Increasing the fresh rate to 75Hz does reduce the signal processing time but
it does not show as obvious as the panel itself.
We still recommend 60Hz refresh rate for all LCD Monitors

Not really sure what they are trying to say, but it doesn't matter.

You will not see anything different with a higher refresh, so don't
worry about it.

 

[Bob Myers]

I have a new Samsung 940B analog/digital monitors. It has a refresh rate of
8ms but the recommended screen refresh rate is 60hz. I am told that 8ms
monitors should be set to 75hz to obtain the 8ms refresh rate.

Is there a reason why Samsung recommends 60hz rather then the fast capable
speed of 75hz? Loading the Samsung driver actually hides all other then
60hz.

Very likely because the panel itself is being operated at
a 60 Hz rate, or close to it, regardless of the refresh rate
of the video signal at the input. In other words, for any
input other than a 60 Hz refresh, the monitor's scaler/controller
is performing a frame rate conversion in order to drive the
panel at 60 Hz. Since such a conversion can itself result in
visible artifacts, it's best simply to drive the monitor at the
panel's native rate in the first place.

Bob M.

 

[therowdy via HWKB.com]

Guys...thanks for your information - appreciated.

Do you know of any white papers or sites where this is explained in any
detail?

 

[rjn]

Do you know of any white papers or sites where
this is explained in any detail?

You could do worse than starting with the recent:
"Contemporary LCD Monitor Parameters:
Objective and Subjective Analysis"
<http://snipurl.com/1a5kk> or
<http://www.xbitlabs.com/articles/other/display/lcd-parameters.html>