it could be that the sb is in a shared slot with usb. I also notice that your videocard hasn't been assigned an irq which is not good as I'm sure it needs busmastering to get best performance.
I suggest that 1)you go into bios & disable com 1 or com2 to free up an irq.
2)disable sb emulation in device manager/creative multimedia/sb emulation; this also frees up an irq.
3)move the sb into a different slot which isn't shared.
hopefully with the 2 free irqs, your sb will be assigned an unshared irq & your videocard will also get an irq, hopefully to itself.
let us know how you get on
btw its ok to have a piece of hardware sharing an irq with pci steering.