Vsync Compromise

[Natty1]

I'm not very good at explaining stuff, nor do I know if anyone here will know what I'm talking about but I thought I'd still give it a shot:
I have been wondering this for a while, but after playing lots of console games (most notably Xbox games), they seem to have hit somewhat of a Vsync compromise, where as long as the framerate is running at it's peak (for example in Metal Gear Solid 2's case 60FPS) the screen won't tear, however if the games framerate drops for any reason the game seems to somehow turn the Vsync off in order to maintain the highest framerate possible.

From what I gather about Vsync if it was locked on and the game drops even 1FPS then the game would display 30FPS instead of 59FPS being that 30FPS would be the next multiple of 60hz which happens be an NTSC television refresh rate.

My question is has anyone managed this technique on the PC? I tried setting Half-Life's maximum FPS at 60FPS at the default screen refreshrate of 60hz I then turned Vsync off (since theoretically this would stop any tearing as long as the framerate remained at 60FPS which it did) but alas, the screen still had a little tearing, strangly enough moreso using a wireless mouse then using the keyboards curser keys.

I'm not sure if anyone knows what I'm talking about but some games that use this technique of the top of my head are:
Metal gear Solid 2, Project Gotham Racing 2, Tenchu 3: Return from Darkness.

 

[Asus]

Not really sure. Perhaps the tearing after you set the 60FPS limit was because it went under the framerate. Or didn't it?

Only thing I can tell ya is to try setting your refreshrate higher (85Hz) with Vsync enabled. Then adjust res/quality settings to get good framerates so it does not dip below (85/2=42.5) 42.5 FPS. 40FPS is still pretty playable.

If you have an ATI card you could use Temporal AA as that needs Vsync to work but if you dip below it shuts off Vsync and Temporal AA til your FPS goes back up.

 

[DSDchemE]

I think I can answer the tearing at 60Hz part, but not sure about the rest. While your computer may be rendering at the same rate as the screen-display, it may not be in phase (meaning the screen might display right before the rendering finishes).

--------- | Vsync On | Vsync Off
Render: |--__--__-- | --__--__--
Display: |--__--__-- | -__--__--_

Edit: not sure about that though.

My guess for the other part (running at 59fps with Vsync on): I think that Vsync just slows down rendering to your display speed. So if something doesn't render fast enough, it'll just display the old image for an extra frame. Not sure what effect THAT would have though. I don't think that it switches to 30 fps though (at least not on mine).

Also, if I have a slower system (30-45 fps normally), would it be better or worse for me performance-wise to have Vsync on?

 

[Natty1]

Thanks

Well the game I tried was Half-Life (1) on a Nvidia Geforce 4 MX440 and the framerate was definitely keeping up at the 60FPS mark.
This temporal thing seems to be what I'm looking for though, thanks.