its not drivers its hardware based if you look through creatives forums long enough about people complaining they basically in the end said sorry its a pci problem with the bus on NF4 chipsets.. causing it, talk to nvidia.. and there in lies the dead end...
heard nothing at all about it since
no drivers, no updates no nothing.
X-Fi + NF4 chipset + Vista = crackling
the best part is, it isn't localized to JUST NF4 chipsets.. there are MANY others and still no sodding fix
which is a shame because i loved vista apart from the crackling no matter what i did
maybe using the PCI-Ex bus will stop it?