Unity is already disabling most of effects when using sw-rendering, we can check how to reduce this to the maximum, but I think that at unity level most of the elements have already been addressed.
The problem when moving the windows affects compiz also when unity is not loaded, so I don't think unity impacts much on that.
From what you say on description by the way, I believe that you were using unity-2d on that setup, at 12.04 times, but it has been deprecated since 12.10; so simple new compiz can't be compared with the one at 12.04.
Unity is already disabling most of effects when using sw-rendering, we can check how to reduce this to the maximum, but I think that at unity level most of the elements have already been addressed.
The problem when moving the windows affects compiz also when unity is not loaded, so I don't think unity impacts much on that.
From what you say on description by the way, I believe that you were using unity-2d on that setup, at 12.04 times, but it has been deprecated since 12.10; so simple new compiz can't be compared with the one at 12.04.