Epson ActionDesk 4000 User Manual page 102

Note
Not all hard disk drives can take advantage of this feature.
To take advantage of the local bus IDE interface, your hard
disk drive must support a 32-bit data path that utilizes
double-word I/O. To find out whether your hard drive
utilizes double-word I/O, see the hardware specifications
for the drive or contact the vendor of the drive and request a
product specification.
6-6
Installing VGA and IDE Drivers