Problem with SB X-FI Titanium Fatal1ty

Hi everyone, I've used this Forum to solve so many problems, and now I need help for a problem that i can't solve.

My Specs:
Intel Q9650
Motherboard XFX 790i Ultra Sli
Ram 4gb DDR3
2 x GTX280 XFX 640MHz 1gb (SLI)
PSU 1000W Enermax Galaxy DXX
Windows Vista Ultimate 64-bit

And... a "lovely" Creative Sound Blaster X-Fi Titanium Fatal1ty PCIe

I have the sound card instaled, and with the drivers that came with it.
But I've got a problem. With some games it makes a noise... very disgusting (the sound is similir to the one that makes a radio when it can't get the freqency... interference, it sounds more or less like chakchkachakchakchakchak....).

It happened with Call Of Duty World at War when i throw a gas greanade (but it happens since i upgrade the drivers and the creative console so i downgrade it to the version of the cd and the problem was solved).

With other games like Grand Theft Auto IV it happens more. If you're in a place with Smoke it sounds and at the menu when you select things...

I noticed that if i use a lower audo Quality (the minimum quality that i can use is 16bits 44100MHz), the noise is lower than if I use a better quality (the bigest quality 24 bits and 9600MHz makes a very loud noise). I tried to desactivate the Sound Blaster enhacements and everything but the noise continues.

I think that i have enough PSU, and the Integrated audio card works perfectly (well the quality ofcouse is lower but it never fails, so I'm using it)

Sorry about my english.

I hope you'll find a way to help me

Thanks !