HD ata, pata, ide and ultra ata

Hi, I own a Power Mac G3 desktop beige and I've bought a new HD Western Digital 80GB WD800AAJB 7200 rpm 8MB Caviar Blue PATA. The Mac sees the HD as it complies with G3 limitations (no bigger than 120), mounts it, formats it, uses it, but just for "normal" use, I mean writing, reading files. But when I try to use it in HD recording mode, with Pro Tools, the drive seems to work, but when I play recorded files, they appear to be fitted of spikes, and I get a crackly sound, like the old dusty vinyl one. If you examine the waveform, made with a sine test, you can find many, many spikes everywhere.

Can I fix it? may be with a special drive? Or is it an insoluble problem?

The OS is 9.2

Thanks to everybody

massimiliano