You are not really going to see much difference between 25fps and 30fps recording. (Of course some will claim that they can )

What happens sometimes with N900 is that the frame rate during recording temporarily drops below 25fps (or in other words frames are dropped during recording) if the phone is heavily loaded. This is probably why the N95 seems better to you.

So I think that the improvement should not be an increase in frame rate but rather that the N900 is able to maintain the 25fps frame rate during recording (even when it has other processing to do in the background).