No there isn't. while the x-fi xtreme can handle gaming audio better I've found most games just don't make use of that many sound points. And in stereo sound there isn't any difference between onboard and dedicated cards anymore. I think a lot of people mistake the effects that the software equalizers that come with the hardware have as "improvement". But that's just me.
Don't waste your money. If you don't have a surround sound system then I wouldn't bother using the audigy 2 over the onboard.
I would like a soundcard that can offer good 3D audio for games. So that i can locate enemies in using sound in games like battlefield. I will also get a 5.1 speaker system maybe the logitech x540. What i wanna know is that if x-fi can give better sound than audigy 2 zs.