LCD screens and VSync

[Paul]

Whilst reading a thread over at Rage3D about Vsync, something occured to me.

If your FPS is lower than the refresh rate of your monitor, your FPS is effectively cut in half, correct? So for example if you were running at 85hz, but could only get an FPS of 70, you'd run at 35fps. If you're above the refresh rate, your fps is capped to whatever your refresh rate is set to.

All well and good.

But - LCD screens have a much lower refresh rate than CRT screens. My question then, is this: Does the same VSync rule apply? If an LCD had a refresh of say 40hz, would my FPS being cut to 20 if i couldn't exceed 40fps?

[Riptide]

Forget refresh rate, it's response time that matters more than anything with LCDs (measured in ms).

I haven't noticed a great deal of difference whether running with vsync on or off. YMMV...

[Paul]

I'm talking about FPS, which is affected by Refresh Rate. I know refresh rate doesn't have the effect it does in general terms on CRT screens.

[Riptide]

Well, unless your talking about the new NEC that has the 16ms response time most LCDs aren't going to approach 60fps anyway...

[ricercar]

All current consumer LCD displays are limited to 60 Hz refresh, which for the purpose of this discussion also caps frame rate at 60 FPS. This limitation of consumer LCDs is one of the critical reasons why a CRT is still king for gaming.

While my GF FX gives me 320+ FPS in 3DMarks, on a LCD I can't SEE any difference from my Ti4600's or GF3. Anything over 60 FPS all looks the same on a LCD. But running 3DMark it on a CRT, even my non-gamer spouse notices the frame rate improvement.

[nin_fragile14]

Originally posted by Paul
Whilst reading a thread over at Rage3D about Vsync, something occured to me.

If your FPS is lower than the refresh rate of your monitor, your FPS is effectively cut in half, correct? So for example if you were running at 85hz, but could only get an FPS of 70, you'd run at 35fps. If you're above the refresh rate, your fps is capped to whatever your refresh rate is set to.

All well and good.

But - LCD screens have a much lower refresh rate than CRT screens. My question then, is this: Does the same VSync rule apply? If an LCD had a refresh of say 40hz, would my FPS being cut to 20 if i couldn't exceed 40fps?

Yes. I'm running an LCD right now. V-sync maxes at 60, if it doesn't hit 60, it cuts to 30.

[StealthHawk]

Originally posted by nin_fragile14
Yes. I'm running an LCD right now. V-sync maxes at 60, if it doesn't hit 60, it cuts to 30.

eww, that's not good. I had almost convinced myself to buy a LCD.

[Paul]

Hmm, all this is turning me off choosing an LCD for my next monitor. Having said that, given the whole system is getting an overhaul, i should be able to keep it above 60 anyway. Although higher FPS would be nice, i can't see that you'd notice much difference if it was a constant 60, as opposed to varying 50-80fps?

The only worry is dropping down to 30fps if i can't hit 60. For CRT screens it would be fine, since you'd be looking at a cut score of around 40-50. Hmm.

[eL_PuSHeR]

If I have understood it correctly, by having VSYNC disabled, your frame rates would vary between 0-60fps, being 60Hz the max refresh attainable, right?

[StealthHawk]

Originally posted by eL_PuSHeR
If I have understood it correctly, by having VSYNC disabled, your frame rates would vary between 0-60fps, being 60Hz the max refresh attainable, right?

no, if vsync is off then you are NOT limited by refresh rate.

you are still limited by the pixel response time though(ie, how long it takes for a pixel to change from one color to another). currently the state of the art LCD monitors have a response rate of 16ms which equals 60fps. chances are your LCD will have a higher response rate, which will lower the maximum real framerate you can get.

[eL_PuSHeR]

Thanks. That's why the lowest possible pixel response time is very important for LCDs/TFTs, and that's way they're not so good for gaming, due to the 'ghosting' effect.

[-=Gib-McFragger=-]

I game on my Samsung 172T fine, with very minimal ghosting only in extremely fast scenes, like fast cut-scenes for example.

Normally I don't even notice it. As for Vsync, I have never used it, and have no probs with tearing. :)