User blog comment:Gundam Legilis/RWBY Vol 3: Enter the Dillon/@comment-10380701-20150728033337/@comment-25555436-20150729141701

We are confusing "slower" here. I thought when Phantom said laggy, it was in the same way that many Vocaloid videos are, in which it seems like the animation stops a bit for a second, like it skips a frame or 2. In such case, more frames are needed to "complete" the animation, otherwise the animation looks weird and ugly.

Now, if you want something that gotta go fast you can use less frames, with the speed hiding the lack of them (until someone pauses at the right time). However, it's not hard to reach the same speed with more frames; video editing. You finish the animation. If a scene's animation seems to be too slow, speed the video up slightly so it reaches a reasonable speed (obviously, adding the VA comes after that).