In the last months more and more motherboards with integrated IDE RAID controller have become available. Even though SCSI might still be the one and only choice for professionals, IDE has become a powerful interface today. Using two or more drives in a RAID 0 configuration will boost your hard drive performance considerably. You only have to buy the additional hard drives of course.
The second reason that speaks for IDE RAID is data safety. Most controller chips are capable of running two or four hard drives in RAID mode 1 (the so-called 'mirroring'). You will only get marginally better drive performance while sacrificing half the capacity, but your data will be disproportionately safer, since the controller will simultaneously write every Byte twice.
Usually you can also combine those two modes by using four drives: Data will be split on two hard drives and mirrored onto the other two drives at the same time. This way you will get a fast and very safe IDE subsystem.
Using UltraATA/100 Drives With A Slower Interface
Lots of readers keep asking us what might happen if they attach a modern ATA/100 drive to an older controller (UltraDMA/33 or UltraATA/66). Basically the drives are compatible with all former IDE transfer modes, including the old PIO modes 0-4. A ATA/66 controller is fast enough for ATA/100 drives. Even if you want to use one of the three drives with an ATA/33 interface, you can still do it without losing major amounts of performance. Of course the data transfer rate will be reduced by the slower interface, but at the same time you can be sure that the interface is fully used. Just make sure you have an adequate amount of RAM in order to reduce unnecessary interface activity by Windows using the swap file. People who are still using older Pentium boards with a PIO hard drive should consider a new basic system before upgrading to high-end hard drives.