Buzzing in speakers with new video card

[Azndude51]

My friend had a Dell 4700 running on integrated graphics and sound. I helped him install a new X800GTO into his PCI-e slot. Now whenever he moves windows or icons around on his desktop, there is a buzzing sound from his speakers/headphones. It also happens when a lot is changing on screen like in games. Anything to fix this? Is it just interference? do you think getting a sound card would help?