What kind of support will Unity provide for Nvidia cards?

Solution 1:

The idea is if your driver supports 3D you will get Unity, if your driver or hardware does not you will get a standard GNOME 2.x desktop.

Unity itself will be built using Compiz technology which gives us the ability to have a fallback mode for 2D, this is why we can become highly performant, which we couldn't do with Mutter as it required 3D accelleration. More information will be made on the blueprint.

RAOF's answer also has more information.

Solution 2:

Everything Jorge said but also nouveau can already render basic things in 3D through Gallium3D.

This feature isn't turned on by default because it's relatively unstable and it can break things. This could be mature enough for implementation by 11.04 release.

Solution 3:

It's quite likely that the 3D support in the open-source nouveau drivers will run Unity well. However, upstream is not currently in a position to support their 3D component, and so neither will Ubuntu. As in Ubuntu 10.10 it will be possible to install the nouveau 3D support from the libgl1-mesa-dri-experimental package, but this will not be installed by default and we will be unable to do anything useful with bug reports about 3D.

It's also possible that power-management support for nouveau will land in the kernel that will be used for Ubuntu 11.04, but that's not clear yet.