pcm driver kills SMP performance

[matthew tillman]

Hello-
I have an ACorp Dual P3 motherboard, with a pair of P3 733s.  My sound card, is a SoundBlaster Live Value.
 
Whenever sound support is compiled in the Kernel, performance takes a huge hit, X runs about the same as on a P2 300 or so.  But If I boot to a kernel that is configured exactly the same, the system is very responsive.
 
I first had this issue with 5.1-Release.  I then CVSuped to -CURRENT, and still have the same issue.
 
I also tried swapping the card into a diffrent PCI slot, but that didn't help.
 
Any ideas?
Thanks,
Matthew