sine wave drawing slowly in fcp and sound track

When I turn on the sine wave in the audio tracks on FCP they dont show up or draw very very slowly. I am talking about 5 min or more for a 15 min sequence. This same issue happens in Soundtrack pro. I can hear the audio but the waves take forever to draw.
Running on a G5 quad with 8 gigs of ram.
This is a fairly new experience. Could it be that my drive space is to low. I realized that I am down to 10 gigs on a 500 gig drive.