I finally got around to replacing the broken IDE cable in my computer last night. It had been limping along with an old UDMA33 cable, and now has a proper UDMA100 cable.
Before:
damo@omad:~$ sudo hdparm -t /dev/hdc /dev/hdd /dev/hdc: Timing buffered disk reads: 86 MB in 3.07 seconds = 28.05 MB/sec /dev/hdd: Timing buffered disk reads: 86 MB in 3.06 seconds = 28.14 MB/sec
After:
damo@omad:~$ sudo hdparm -t /dev/hdc /dev/hdd /dev/hdc: Timing buffered disk reads: 172 MB in 3.01 seconds = 57.15 MB/sec /dev/hdd: Timing buffered disk reads: 170 MB in 3.02 seconds = 56.23 MB/sec
Now my media drives are running approximately twice as fast. I should have done it months ago!