I have built a DAW recently (see system spec below) and have some problems with the (2nd) audio hard drive... it's slow!
The audio disk is 17% full and defragmented. When opening a project just with a stereo track, and going back and forth to the beginning and end of this track (using numeric pad keys 1 & 2), the VST performance window shows peak for the audio hard drive. Weird. Also, when loading a VST instrument, it takes a looong time (it would stops for a sec, then continue loading, then stops again).
I just tested both hard drives with Roadkil's Disk Speed Version 1.1. Here are the results: