Back in 2005, SATA was a big step forward for the Mac. The original SATA specification supports transfer rates up to 1.5 Gb/sec. Most Macs used UltraATA at 66 or 100 GB/sec, and SATA had 50% more bandwidth than UltraATA 100. From there, SATA has become even faster.
SATA I was used on G5 Macs and early Intel-based Macs. The original Mac Pro was the first Mac with 3.0 Gb/sec. SATA II in August 2006, the iMac went there in Mid 2007, the MacBook made the transition in Late 2008 with the Aluminum MacBook along with the MacBook Pro, the Mac mini went SATA II in Early 2009, but the MacBook Air didn’t get SATA II until Late 2010.
The next jump was to 6.0 Gb/sec. SATA III, which surprisingly never made it into the Mac Pro line. The Early 2011 MacBook Pro has SATA III, and the MacBook Air got it in Mid 2011, as did the iMac and Mac mini. The next step was to PCIe SSDs, which is beyond the scope of this article.
2.5″ SATA SSDs
The easiest solution is to install a 2.5″ SATA Solid State Drive. If your Mac has SATA I, stick with SATA I hard drives. There’s no real benefit to a faster SSD, and sometimes SATA II and III drives don’t work well on a SATA I bus.
If your Mac has SATA II or SATA III, buy a SATA III SSD simply because they are all backward compatible with SATA II and they tend to be more cost effective than the handful of SATA II SSDs on the market.
2 Drives in 1 Slot?
There are drive adapters for putting 2.5″ drives in 3.5″ drive slots, but if all you’re adding is an SSD, that may not even be necessary – Velcro™ might be all you need.
However you might want to consider an adapter that lets you puts two 2.5″ drives in a 3.5″ slot if your Mac supports it. Unfortunately most Intel SATA controllers don’t support port multipliers, so my 2010 iMac, for instance, doesn’t have that option.
I like to use a conventional hard drive to store downloads, my iTunes library, and other things where speed isn’t a big deal or files are just going to sit there (software download files for instance) and use the SSD for the Mac OS, all of your apps, and most of your work files. I also put a Mac OS X 10.6 Snow Leopard partition on the hard drive for the rare time that I need to boot into it.
After all, why buy an SSD with more capacity than you really need when a hard drive and a slightly smaller SSD can save you money? (480-512 GB SSDs seem to be the sweet spot for price and capacity these days.)
Because databases that are heavily accessed put heavy demands on an SSD when making updates, you may be better off storing your databases on a hard drive, in which case you may want a faster hard drive with a bigger cache to optimize database access. Other than that, a slow 5400 rpm drive will probably be just fine.