Ogre was a true Direct3d Engine in the past and was ported to OpenGL, but it uses the OpenGL pipline in the wrong way.
Another solution wasn’t possible because the conept is based on rules how DirectX works (Ogre is ok for DirectX but not for OpenGL).

For an OpenGL pipeline your program must work this way:

while(run)
{
clean_back_buffer
draw_all_geometry
do_all_cpu_works
swap_buffer
}

Ogre does it NOT this way.
It blocks the whole programm in the swap buffer.
-> CPU lag and slow spead

If you want write an OpenGL based game, don’t use Ogre! (but as i said, it is ok for an DirectX based game)

And here Crystal Space is much better, it was designed for the OpenGL rendering pipline in mind
and is because of that a lot faster than Ogre in OpenGL.

bring it on!
;)