Is gnome classic (no effects) noticeably faster than ubuntu 2D? Should I use it, since I only have 1Gb of ram?
Also, you can only move the unity bar to the bottom in unity 3D right?
Thanks in advance.
In general, when you use a compositing manager (which is used for desktop effects in Unity), there will be more overhead than when you don't. It shouldn't be more than your machine can handle with that amount of RAM, though. If you're looking for a more efficient window manager, check out XFCE or LXDE.
I don't think that the Unity bar can be moved at all, regardless of whether Unity has effects enabled.