You can check your Macintosh System Profile. When you select the installed eSATA card, the Device ID will show either "0x6081" or "0x5081". The 3 Gigabit/second eSATA cards use the Marvell chip 88SX6081. The 1.5 Gigabit/second eSATA cards use the Marvell chip 88SX5081.
A very small number of Tempo-X SATA 4+4 users have reported a condition in which connected drives installed in an external case intermittently do not appear when their computer is booted.
To address this issue, update the Tempo-X SATA 4+4 card's firmware to version 1.0.1 or later by downloading and running the latest Tempo-X firmware updater.