Forcing refresh rate to other than 60Hz

[Jarko]

Is there any way to force the refresh rate of the T60 LCD to other than 60Hz? In power management there is an option to lower the refresh rate to 50Hz or 40Hz when power source is battery, but could this be applied somehow when power source is AC?

I'd like this because PAL DVD material is 25fps and with 50Hz it would be perfectly smooth playback. (Haven't tried ReClock with T60 yet, but it would ensure this.)

Any ideas? Will Powerstrip do the trick?

What about the VGA-out? Can it be set to different refresh rates than 60Hz?

[kamaleon]

What exactly do refresh rates do on LCD displays? Never figured that out...

[Jarko]

What exactly do refresh rates do on LCD displays? Never figured that out...

Well the screen doesn't flicker like CRT screens. That's no problem.

But it is still updated at some specific speed like 50Hz, 60Hz, 75Hz. And when watching a video at 25fps the refresh rate should be 25Hz, 50Hz, 75Hz or 100Hz to ensure smooth playback.

There is also other problems in getting smooth playback but these are fixed by software named ReClock. These problems are PCs different clocks for display adapter and monitor and sound etc. Google ReClock and you'll find good explanation to these.

[JHEM]

What exactly do refresh rates do on LCD displays?

Absolutely nothing!

James

[Jarko]

What exactly do refresh rates do on LCD displays?

Absolutely nothing!

James

Weird comment. They do something and with media playback they are crucial. Just read some deep thoughts about new flat LCD TVs

No offense but why you just ignored my reply to this thread?

-Jarko

[kamaleon]

This whole issue is very obscure for me. I have heard about reclock, yes, down at AVS forum and Doom9 and stuff people are going mad about it.

I need to investigate it. Do you reckon a bad refresh rate on LCDs causes motion judder?

I've never realised why my samsung 193P display has both 60 and 70Hz available. I think there's not enough common knowledge of this going around.

[Jarko]

This whole issue is very obscure for me. I have heard about reclock, yes, down at AVS forum and Doom9 and stuff people are going mad about it.

I need to investigate it. Do you reckon a bad refresh rate on LCDs causes motion judder?

I've never realised why my samsung 193P display has both 60 and 70Hz available. I think there's not enough common knowledge of this going around.

Yes this is just what I'm talking about, motion judder.

Although the LCD screen isn't refreshed same way as CRT it still is refreshed at some speed. This shouldn't be hard to understand, to show the movement, the display adapter has to update the screen at specific speed, this is like 60 or 70Hz. And if you can't divide the LCD monitor Hz with the fps of your video material, you get motion judder.

Now it gets a little more complicated. Let's assume that you watch 25fps PAL material and your refresh rate is 75Hz. Everything should be fine, right? 75/25=3? Everything OK, no judder? NO, this is not the case. It still can and will be not-so-smooth.

PC has complicated clocks in various components, soundcard, display adapter. So these have to be synchronized. ReClock does this. Download ReClock here and read the documentation and there will be light : http://reclock.free.fr

Now all this doesn't mean that you get very bad motion judder like you can't watch a PAL movie when your T60 has 60Hz. It doesn't judder that badly, but when you know what to look for to notice the not-so-smooth-playback and have studied these things and have an obsession for movies, you just want them to be perfect.

[kamaleon]

Hmmm... interesting stuff.

I'm in PAL land too, and i'm a satellite on pc enthusiast. So i suppose i know where you're coming from. But, i thought the motion judder i see came from both the deinterlacing and the response time of my lcds (samsung 19" as i said above and the one from my lenovo 3000 N100). Is there any sort of screen captures or a video or something that could illustrate the motion judder you claim to be caused by a bad refresh rate?