Review: StarTech S252SMTB3, Two Bay Thunderbolt HDD/SSD Enclosure

As many Apple Mac users will attest, the selection of Thunderbolt compatible peripherals on the market is still rather limited. StarTech launches its first attempt at offering a Thunderbolt device with the S252SMTB3, a two bay external drive enclosure. Retailing at $326.99, the device supports up to two 2.5 inch HDDs or SSDs with capacities of up to 2TB each. The unit only supports the initial Thunderbolt 1.0 standard, limiting its maximum data throughput to ten gigabits per second, but that’s still double the five gigabits per second maximum supported by the USB 3.0 standard, and arguably more than enough for any of today’s SSD or HDD drives. (It also helps ensure compatibility with some of the early Intel PC motherboards providing a Thunderbolt port.)

Physically, the enclosure is a silver aluminum box, with the “cheese grater” hole pattern on the front that compliments Apple’s Mac Pro towers, at least the models before the recent Mac Pro cylinder redesign. It uses an external AC adapter “brick” for power, which is nearly the length and half the thickness of the enclosure itself. A white Thunderbolt cable is included, which is notable, considering the $29 pricetag to buy one separately from Apple. Two thumb-screws in the rear of the enclosure allow a hinged back panel to flip down, exposing aluminum drive trays that slide out from the back. Below the hinged panel are a pair of Thunderbolt ports so the enclosure can be daisy chained with another Thunderbolt compatible device, and the AC power jack to their left.
For testing purposes, I installed a pair of 240GB Crucial M500 SSDs. I imagine most users interested in external Thunderbolt storage would prefer more total drive capacity than this, but it’s important to remember that this enclosure isn’t designed for 3.5 inch desktop type drives. Large capacity 2.5 inch notebook form-factor drives are still less common and more costly than their desktop counterparts, so this is all I had readily available.

I connected the enclosure to a mid 2013 15″ retina Macbook Pro running OS X 10.9,2 Mavericks, and benchmarked the disk speed using the BlackMagic drive speed test. The software reported a disk read speed of approximately 379MB per second, and a write speed of approximately 269MB per second. By contrast, running the same test on the built in 256GB PCIe SSD in the Macbook Pro produced more fluctuating results, with disk read speeds generally around the 329MB per second mark and write speeds somewhere around 278MB per second. These minor fluctuations were likely due to the operating system using the drive for other background tasks during the speed test. Regardless, the results indicate the StarTech enclosure is capable of giving performance very similar to what one could expect from a fast internal drive.

Overall, I can safely recommend the StarTech as a viable option for external Thunderbolt drive storage. The unit was successfully detected and the drives properly mounted whether I had it attached before powering up the computer or plugged in the Thunderbolt cable after OS X was up and running. I do have some concern that the tiny cooling fan on the rear of the unit might eventually fail, but that’s simply based on previous experience with similarly small fans in other enclosures. StarTech promises a full two year warranty; beyond that time-frame, one could likely source a nearly identical replacement fan and replace it inexpensively. Otherwise, there were no real issues with the unit during testing. Users in need of very large amounts of external disk storage might be better served with a product supporting 3.5 inch desktop SATA drives, but the StarTech makes a lot of sense if you want the fast performance of SSDs.