Believe it or not, there is one developer who is co-opting graphics processors to do audio DSP. http://www.soundonsound.com/sos/oct09/articles/pcnotes_1009.htm

I'm guessing you aren't needing to do this, so probably not worth the bother. What's interesting is that graphics processors are becoming as expensive or more expensive than CPU - thank the gaming industry for that.

-Scott