Thumb Drives: Introducing 128 GB USB And High-Speed eSATA

Introducing eSATA… Kind of

eSATA and USB combined: Our test motherboard offers an eSATA port, which also has USB 2.0 connectors in order to provide device power.

eSATA is a physically-modified interpretation of Serial ATA, optimized for external devices. The connectors are slightly different, and the minimum voltage levels are increased to ensure reliable operation. Depending on the SATA controller, eSATA supports either 1.5 Gbit/s or 3 Gbit/s operation, resulting in 150 and 300 MB/s bandwidth using 8/10-bit encoding. The practical limitations are the maximum cable length of 2 meters, and controller support via your operating system—devices using the Advanced Host Controller Interface (AHCI) are the most flexible. eSATA is much faster than USB 2.0 (480 Mbit/s) or FireWire 1394a and 1394b (400/800 Mbit/s).

eSATA Utilizes USB to Power External Devices

Of course, the interim solution for external devices is to get power in some other way. Using an external power supply would not make a lot of sense for thumb drives, which are meant to be ultra portable. Hence the only solution lies in accessing existing interfaces such as USB 2.0. All three eSATA drives we reviewed are combo drives, meaning that they support either eSATA or USB 2.0 through different interfaces. All three utilize JMicron’s JMB362 controller, which supports both standards. If you connect USB 2.0 first, the drive will establish a USB 2.0 connection and use it for power and data. To use eSATA you have to plug in that connector first, and create a USB 2.0 connection using a dedicated USB 2.0 cable to get power to the unit.

eSATA + USB

The MSI 790FX-GD70 motherboard we used to test the devices offers an enhanced eSATA port with additional pins for USB 2.0 power supply, which the three eSATA drives support. Although this is not specified by the SATA IO, the approach worked fine during our testing.