I think I found a combination, that could fix this problem. I have been trying around the past few weeks and asking in different forums. Eveyone suggests something else, so I will post what I did, to get rid of the Vsync/tearing issue, in combination with Compiz (I play 720 and 1080p Videos without a prob. now and with no tearing whatsoever). Tested with Ubuntu 10.10.
1) Download CCSM and install it. Make sure you have the new Nvidia drivers (prop.), that Ubuntu should offer you.
2) Enable Vsync in CCSM (general options/settings) and disable the automatic refreshrate detection (it always gets it wrong with Nvidia cards) and set it manually to 60 or 120.
3) Do a sudo nvidia-settings in the terminal and enable Vsync for XV and OpenGL (Video and 3D) and allow flipping in OpenGL.
So far so good, eh? Nothing special so far. I always had tearing, even with all these settings, BUT recently I added this:
4) Open up your xorg.conf by doing a sudo gedit /etc/X11/xorg.conf in the terminal and putting this in the file that opens (where the other Device/Screen Options are listed): Option "TripleBuffer" "True"
5) Save and reboot your computer, just to be sure.
6) Done. If you want accelerated Video and you have an Nvidia card, you could also use VDPAU. Download Mplayer via Software Center and enable VDPAU as output there. Works only with Gefore 8 series and above. Also, I have been testing the new Adobe Flash 10.2 Beta and everything seems to be working O.K. No tearing with flash, no tearing with videos, no tearing on the desktop. Everything awesome so far.
If anyone wants to try it out and report back, do so! I would like to know if I am just having good luck or if this actually helps reduce tearing. I have yet to see any tearing at ALL.
I have done this in many 3D games, so I thought it might help with Compiz, since I never read about anyone trying this combination.
Vsync ON: Performance decrease but no tearing.
Vsync ON and DoubleBuffer: Performance is better but framerate ist "cut" in half. Example: 60hz LCD; if you can't get those steady 60fps and sink a few fps below those 60fps then you're at 30fps suddenly. During this I sometimes see tearing.
Vsync ON and TripleBuffer: Performance is at its best but it also eats up 50-60% more VRAM. If you have enough VRAM, then this should be no problem. No tearing whatsoever.
I will try these steps with an ATI card. I have tested Compiz with Intel GMA chipsets (GMA 900 and 950) and it seems to do Vsync just fine, even without adjusting things and all.