Today, I upgraded the TV I played my games on to an HDTV. I was able to fix the calibration well enough to be playable (I still have RB1 instruments), but I noticed drum fills are really laggy. It takes like half a second for my hits to register through my TV and when I hit multiple pads at the same time, they are not in unison. Is there any way to fix this?

Hm, I never had a lag problem with only drum fills, but playing Rock Band on some HDTVs (like my own) require you to adjust the video settings a little bit to get rid of lag. My TV has a "game" mode, which just tones all of the colors down a tad to make the TV work less. Without it, Rock Band is unplayable on my TV, so check to see if your TV has some sort of "game mode" and maybe that will help.

Hmm, I don't know how to optimize my video settings so that my fills and my regular drumming are lag free. So I guess nobody else has had this problem?