OpenGl: Slow performance with orthogonal projection

[LyhjeHylje]

Hi, I experience huge slowdown(minus 10fps or so) if I use orthogonal projection instead of perspective. There is only handful of polygons and no lighting on the scene and almost no other code running.

Is there something special about glOrtho? The target device is N97.

Update: the problem area seems to be texturing. Is there any known pitfalls(that I don't know)?

Update2: Try'n'error -approach improved the fps to tolerable levels.