My guess is that more likely than the comboburst, it's probably the combofire that's killing. Try switching that off in options and things should seriously improve.
I also had lag from the combo burst when it was first implemented so I quickly turned it off and haven't had it on since that. My graphics card is a nvidia geforce 8600m gt, if the info is of any use.
< mtmcl|irc> Is Gemi just the guy who comes out of nowhere to disagree with things?
Dance Games European Championships 2009 - Rank #10 Dance Games Finnish Championships 2008 & 2009 - Rank #3