Re: No OpenGL or Direct3d icons or settings
The newer drivers don't seem to have the OpenGL and D3D "tabs" or sub-menus that you are used to from the older versions. All of those settings are still there, but you'll need Rivatuner or similar program to change them. However, the newer drivers do include some additional features like application profiles that are really useful.
As far as the "stuttering" or "lag" when loading levels- it is likely a situation where your system could benefeit from more RAM. You could try to turn some settings down, particularly texture detail...