IIe will use the standard Disk II ROM. This ROM will not stop trying to boot a disk in the drive. A few programs need the standard ROM to boot up; most do not. When selected, IIe will use the standard Disk II ROM. This ROM will not stop trying to boot a disk in the drive. A few programs need the standard ROM to boot up; most do not. IIe will use a smarter Disk II ROM. This ROM will stop trying to boot a disk if there is no disk in the drive. This ROM will boot the majority of disks. When selected, IIe will use a smarter Disk II ROM. This ROM will stop trying to boot a disk if there is no disk in the drive. This ROM will boot the majority of disks. IIe will not intercept reads and writes from 5 1/4" disks. This is much slower than intercepting the disk reads and writes, but is fully compatible. If you can’t stand the waiting, try ‘fast’. When selected, IIe will not intercept reads and writes from 5 1/4" disks. This is much slower than intercepting the disk reads and writes, but is fully compatible. If you can’t stand the waiting, try ‘fast’. IIe will intercept reads and writes from 5 1/4" disks. This is much faster than emulating the disk reads and writes, and for most of the time, it is fully compatible. If you find a program that doesn’t load properly, try ‘compatible’. When selected, IIe will intercept reads and writes from 5 1/4" disks. This is much faster than emulating the disk reads and writes, and for most of the time, it is fully compatible. If you find a program that doesn’t load properly, try ‘compatible’.