QNAP SS-439 Pro Turbo NAS device

QNAP's SS-439 Pro Turbo is the company's first network-attached storage (NAS) device to use 2.5in hard drives. Powered by an Intel Atom processor, this four-bay NAS device is extremely fast, but doesn't offer the power efficiency or quiet operation of other 2.5in NAS devices.

The QNAP SS-439 Pro Turbo NAS is much smaller than NAS devices that use 3.5in hard drives but it still has an impressive array of connections: you get three USB ports, two eSATA ports and two Gigabit Ethernet ports that support failover and load balancing. You even get a VGA output port, which can be used to connect an LCD monitor to keep track of the NAS device's status.

The QNAP SS-439 Pro Turbo NAS has a metal chassis. The four drive caddies — also made of metal — are roughly the size of two 2.5in hard drives side by side, but each caddy only fits one drive. This makes the NAS device significantly larger than the Synology Disk Station DS409slim, which also takes 2.5in drives. We had difficulty inserting some 2.5in SATA 2 hard drives, with screw holes often failing to align properly and metal guides on the caddies proving too narrow to fit drives with slightly thicker cases. The metal grooves which lock the caddies in the chassis are too small to slide without fingernails, making them to difficult to unlock. These problems make it difficult to quickly replace a drive.

Once inserted, the hard drives can be formatted into RAID levels 0, 1, 5 and 6, as well as single and JBOD linear drive configurations. The SS-439 Pro Turbo NAS also supports 256-bit AES volume-based drive encryption; it doesn't offer password recovery. The largest 2.5in hard drives available offer 500GB of storage, making the SS-439 Pro Turbo NAS device's total storage capacity 2TB.

Data can be replicated remotely to rsync-compliant devices, and you can also schedule individual drives to backup to external hard drives formatted to NTFS, FAT, ext3 or ext4 file systems. The one-touch copy button can be configured to backup to or from the attached external hard drive.

QNAP's recently released 3.0 firmware is downloadable from its Web site, though our review unit had an earlier version. The new firmware revamps the Web-based interface, making it easier to use. Though the Cover Flow-like home page is slow and unnecessary, the administration interface and individual file and media browsers are significantly improved. The new firmware also allows you to format internal and external hard drives using the ext4 file system, which offers performance improvements and greater file size limits over ext3.

Media functionality includes an iTunes server and a DLNA-compliant UPnP server powered by TwonkyMedia. These worked well, though the iTunes server sometimes failed to work when there was a non-media file located in the designated "Qmultimedia" share. You can schedule BitTorrent, FTP and HTTP downloads, and the NAS device can also serve as a recording device for QNAP's surveillance products.

Synology's Disk Station DS409slim makes do with a 1.2GHz processor and 128MB of memory, but QNAP's SS-439 Pro Turbo NAS device boasts a significantly more powerful 1.6GHz Intel Atom CPU and 1GB of DDR2 memory. This does increase power consumption, however; configured with a Intel X25-M 32GB drive and two Solidata 32GB drives, the SS-439 Pro Turbo NAS consumed 20 Watts when idle; the DS409slim only consumed 11.5W using the same drives. The SS-439 Pro Turbo offers a slight improvement over larger NAS devices in this respect, as the two-bay QNAP TS-219 Turbo consumes 23W when fitted with two 3.5in hard drives.

We tested the NAS device by transferring files from our test PC, which runs a 300GB Western Digital VelociRaptor. In Intel's NAS Performance Toolkit, the NAS device streamed 720p high-definition footage at an average rate of 98.7 megabytes per second (MBps); this is one of the fastest speeds we have seen in a NAS device. It recorded the same footage at 90.7MBps, which means it has strong write performance.

We also conducted large and small file transfers to test the NAS device's capability in the real world. Using 20GB worth of 3-4GB files, the SS-439 Pro Turbo NAS device recorded a write speed of 67.1MBps, a read speed of 76.98MBps and a read/write speed of 38.3MBps. Using 3GB worth of 1MB files, it wrote at a rate of 33.7MBps, read at 48.4MBps, and performed a simultaneous read/write operation at a rate of 24MBps. These speeds are slightly slower than the eight-bay 3.5in TS-809 Pro Turbo, but are significantly faster than the Synology DS-409slim NAS device, which wrote same data at 23.3MBps and read it at 35.7MBps.

Thanks to a beefy processor and memory, QNAP's SS-439 Pro Turbo NAS device provides extremely fast file transfer speeds but consumes more electricity than some other 2.5in NAS devices. Provided you don't require more than 2TB of storage, this NAS device's extensive feature set and comprehensive connectivity make it a great alternative to larger 3.5in NAS devices for small businesses.

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