LCDs and high refresh rates: What happens?

  • Thread starter Thread starter Bert Hyman
  • Start date Start date
B

Bert Hyman

My Viewsonic VP191 and video card combo allow me to select 1280x1024@75HZ
as well as the "optimal" 1280x1024@60HZ. If I do, the monitor's "Info"
display does reflect the changed rate and also shows a higher pixel clock
value.

I didn't think consumer LCD monitors did this; is there any benefit from
selecting the higher refresh rate? Over a short usage period, I don't see
any difference.

The documentation always says 1280x1024@60HZ is "optimal".
 
Bert said:
I didn't think consumer LCD monitors did this; is there any benefit from
selecting the higher refresh rate?
Click to expand...

No. And it puts more of a strain on your video card if you raise the
refresh rate.

A high refresh rate prevents flicker on CRT monitors, but on LCD
monitors, with their relatively slow reaction time, you don't need a
high refresh rate, as they take about 1/60 second or longer to refresh
in any case.
 
Bert Hyman said:
My Viewsonic VP191 and video card combo allow me to select 1280x1024@75HZ
as well as the "optimal" 1280x1024@60HZ. If I do, the monitor's "Info"
display does reflect the changed rate and also shows a higher pixel clock
value.

I didn't think consumer LCD monitors did this; is there any benefit from
selecting the higher refresh rate? Over a short usage period, I don't see
any difference.
Click to expand...

Many LCD monitors have the ability to perform a frame-rate
conversion, which means that incoming video not at the rate
of the panel itself will be converted to the rate at which the panel
is running. This is done basically for compatibility with CRT
display timings; it is to be avoided, though, due to the likelihood
of motion artifacts and other possible problems in the displayed
image. There is no benefit to operating the display with the "faster"
video (esp. since, in all likelihood, the LCD itself is still operating
right around 60 Hz anyway).

Bob M.
 
Bob Myers said:
Many LCD monitors have the ability to perform a frame-rate
conversion, which means that incoming video not at the rate
of the panel itself will be converted to the rate at which the panel
is running. This is done basically for compatibility with CRT
display timings; it is to be avoided, though, due to the likelihood
of motion artifacts and other possible problems in the displayed
image. There is no benefit to operating the display with the "faster"
video (esp. since, in all likelihood, the LCD itself is still operating
right around 60 Hz anyway).
Click to expand...


My TFT's 'recommended rate is 1280x1024 at 75Hz, if I run it at 60Hz I
notice a slight 'shimmering' effect especially on grey backgrounds. (When I
move my eyes around - maybe I'm just sensitive...)

I'm using an analogue rather than digital connection.
 
dick said:
My TFT's 'recommended rate is 1280x1024 at 75Hz, if I run it at 60Hz I
notice a slight 'shimmering' effect especially on grey backgrounds. (When I
move my eyes around - maybe I'm just sensitive...)
Click to expand...

The first rule is to run at the recommended rate. If you don't
know what that is, 60 Hz is a good place to start, but it's NOT
always the recommended or native rate of the panel.

Bob M.
 
Back
Top