I think you'll find in his reasoning that if you are going to use a hard drive for a scratch disk Anything above 160g may slow the drive in terms of seek time... This may cause stuttering in your audio...
However, ra7or has a good point.... I too like the newer SATA Drives as well...
They provide fast seek times and are near comparable to SCSI drives...
You can buy storage on them for pennies on the dollar and there seek times work well with audio...
Hope this helps....