The OWC Accelsior PCIe SSD looks like an IDEAL choice for making a Fusion drive. It can be used in a Mac Pro PCIe slot, or with any Mac having Thunderbolt by installing it into a OWC Helios external case.
UPDATE: careful testing shows ZERO benefit either with the Accelsior PCIe SSD or with a SATA SSD (these are both non-Apple configs, no comment here on Apple’s official setup). All that is seen with non-Apple SSD+HDD fused drives so far is simple, dumb JBOD behavior: SSD fills up, overflows to hard drive, thereafter speeds are hard drive speeds, no migration of files occurs.
Testing was on a Mac Pro. Could it be that the feature has certain requirements?
- Perhaps it has to be the latest chipset from Intel?
- Perhaps the SSD has to be on a SATA III port (Mac Pro is only SATA II).
- Is the version of 'diskutil' used different than that shipped with Fusion-enabled Macs? (the version from 10.8.2 was used for testing).
Researching— a 2012 MacMini will arrive tomorrow.