Ask Max: Can I use an external drive via eSATA connection?
I have a 2GHz Intel core duo iMac.Can I use an external drive via eSATA connection?
Although the Intel-based Macs all use SATA hard drives, Macs do not yet support eSATA without the use of expansion cards. The eSATA standard is a variant of internal SATA. The only substantial difference between SATA and eSATA is that eSATA was designed for external drive use. There are advantages over FireWire or USB that comes from SATA native communication. In external FireWire drives, for instance, data has to be converted into a FireWire-friendly format and then converted back to a hard drive-friendly format, and then it can be written to the disk. This process of converting data eats up little bits of time.
Power Mac and Mac Pro users can use PCI or PCIe cards to add eSATA support. MacBook Pro users can buy a eSATA Express Card. Unfortunately other Macs are not able to use any expansion cards. It would not make sense to make a FireWire-to-eSATA device because that is what you get inside a FireWire drive enclosure. Your best bet is to continue using FireWire or USB external drives.