Abit kt-7 motherboard + sb live! 5.1 = problems?

[martin_hucke 1]

Well i have

duron 800

abit kt-7 Raid mobo

256ram and

sb live! 5.1 and i get like

"cracklings and weird sounds" when a car passes by or a chopper is flying.. WHATS WRONG? (its no the only game... rally championship xtreme has some errors too)

WHY!?