You might also want to make sure your aren't over saturating the IR port, you should try turning down the intensity of the IR emitter on your Tivo until you get a smooth snappy response. My Xfinity Cable Box is known to be sluggish if the IR is turned up too high.

Also set your Tivo device to RF only on the remote, so that your remote and the emitter are double hitting your box with same IR commands.