SCSI versus IDE

Introduction
The popularity of SCSI is increasing rapidly, but this may be due to a misunderstanding. It is often thought that SCSI blows IDE away when it comes to performance. This is not necessarily true. Several factors must be considered when determining which type is better for you.
In most cases, IDE drive outperforms an equivalent drive in the SCSI format. This, coupled with the lesser costs, makes IDE a better choice. In some cases, though, SCSI is better.

Performance
Most PCs use IDE drives because they are cheap and they perform well. But, to look at performance, you need to look at the entire drive.
Many manufacturers release identical model drives in both IDE and SCSI formats. If you look at these drives, they are identical except for the logic board. The logic board on the SCSI drive contains one extra chip. This chip is nothing but a SCSI adapter to allow the drive to work on a SCSI bus. Therefore, most SCSI drives are just IDE drives with an extra SCSI chip.

In these drives, the data has the extra via of having to go through the SCSI chip, therefore performance is usually better on the IDE drive.

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