“SATA standards are all backwards compatible, right? Well, not necessarily,” Daniel Knight reports for Low End Mac. “Researching upgrade options for the 2010 iMac on my desk has been a real learning experience.”

“Some SATA III hard drives are auto-sensing and thus compatible with SATA II and SATA I ports, but some SATA III hard drives are fixed speed only and thus not backward compatible with SATA II Macs (and PCs) unless you can add a SATA III card,” Knight reports. “It does work the other way. You can put a SATA II hard drive in a SATA III computer, and it will work just fine. The hardware on the logic board handles that. But to trim the cost of producing hard drives, several manufacturers have switched to fixed-speed SATA III drives. And that’s not a problem for most computers built since 2011.”

“That is a problem if you’re trying to use a fixed-speed SATA III drive with a SATA I or SATA II computer, such as this iMac,” Knight reports. “Here’s a list of SATA Macs that don’t have SATA III and are thus not compatible with fixed-speed SATA III drives…”

Read more in the full article here.

MacDailyNews Take: Caveat emptor.

[Thanks to MacDailyNews Reader “Fred Mertz” for the heads up.]