Yep, I had a couple of 15k RPM Cheetah's and a couple of IBM 10k drives in the Tyan dually.
Had no idea what or why when I built it - just did. Obsessing at the time back in 2002.
I just checked and there's a Adaptec 2940w controller card left in one of my rigs - no hard drives on it - hmmmmmm.
Oh, here it is, some optical drives - couple of old Plextor SCSI drives - CD ROM 40x and a CD/RW.
Glad I got rid of all that crap. Also junked drive cooler blocks. Running all fans on the hard drives these days.
I spent ~$4k on that Tyan and NEVER used it for anything outside of a little Quake 3 Arena years ago - what a waste!