Sound Issues

[b1chmonkey]

This is a duplicate post, because I began to think that the lack of responses indicated I was in the wrong forum...

I'm hoping someone can help, I haven't been able to determine much as of yet.

While playing the Dawn of War game (PC version), I get quite a bit of sound chopping, especially during cinema sequences. Since I am work, I dont have my dxdiag spaces or warning logos with me, but you can view them here: http://forums.relicnews.com/showthread.php?t=67477

I have a Powerspec 8822

Processor: Intel� Pentium� 4 Processor 2.53GHz
OS: Microsoft� Windows� XP Home Edition
System Board: FIC VI-39L
System Memory: 512MB DDR266 SDRAM 184-pin DIMM
Hard Drive: 80GB Ultra ATA/100 Hard Drive
CD-RW Drive: LiteOn 52x24x52x CD-RW Drive
DVD-ROM Drive: 16x DVD-ROM Drive - LTN-163
Video: Integrated SiS 651 VGA Chipset; open AGP slot
Sound: Integrated AC'97 Audio CODEC

The computer is stock, other than the ATI Radeon 9550 that I just installed. DirectX is version 9.0c.

I have updated the sound drivers and have looked at tasks running in the background, but cant determine what might be the power culprit.

My questions are this~
1) Will getting a new sound card eliminate the problem?
2) If so, how do I disable the onboard one?
3) Is this maybe a power issue? I have the supply that came with the computer, it's basic I'm sure.

Thanks all.