SBLive! A hog under XP?

Howdy. I don't know about other versions of Windows,
but under XP the SBLive! (latest drivers) seem to be
hogging "something". If I play CS (or any other FPS game)
with the Soundblaster (as opposed to the onboard sound)
enabled, then I get severe FPS drops. If I disable the SBLive!
and enable onboard sound then I suffer no such drops. My
basic spec. is XP 2400+, 512Mb RAM, Ti4200, VIA KT133
chipset. I've tried a couple of potential patches curtesy of
Georgy Breese (http://www.georgebreese.com/net/software/)
but none make any difference.

Has anyone else suffered this indignity? Perhaps even discovered
a solution? Is the Audigy just as bad, in this respect, as the Live!
card?