The Promise SmartStor NS4600 4-bay network-attached storage (NAS) device can provide up to 8TB of storage for the home or a small business. It performed well in our file transfer tests and has an attractive design. However the configuration software and Web interface are difficult to use and its backup options could be improved.

The Promise SmartStor NS4600 is certainly one of the sleeker looking NAS devices we've seen, with rounded edges and a glossy black case. Neon blue LEDs indicate disk power and operation, as well as network and general activity. The only physical button on the SmartStor's front panel initiates the scheduled Snapshot one-touch backup function, which provides up to four restore points on a specified volume.

On the back of the SmartStor NS4600 NAS device there is a Gigabit Ethernet port, a power button, two USB ports and an eSATA port. The USB ports can be used to access flash drives and share USB printers. Unfortunately, they won't work with external hard drives that don't have an external power supply, and the USB and eSATA ports don't support HFS or NTFS file systems; only FAT32 and EXT3 support is available.

Despite the attractive design, the SmartStor NS4600 NAS device's build quality could be improved. It has a plastic feel and employs small plastic rails instead of the larger drive trays found on the Proware DN-500A-CM and QNAP TS-439 Pro Turbo NAS. Promise claims the rails prevent drive vibration, but we haven't noticed this problem on other NAS devices.

Screwing drives into the rails can be difficult and inserting and removing the drives isn't easy either; we would have preferred metal trays instead. Drive bays can't be locked individually, but you can lock the drive bay door to keep out prying hands. The drives are hot-swappable and can be configured to RAID levels 0, 1, 5 and 10; there is no JBOD option.

The set-up process isn't as intuitive as it is with friendlier NAS devices like the Western Digital Sharespace. The SmartStor NS4600 NAS device isn't visible on a network until drive volumes are configured, which can be done through the accompanying SmartNAVI software. The software discovers available NAS devices and provides an icon-based replacement for the Web interface. It can be used on either Windows PCs or Macs.

SmartNAVI allows you to set up the drive's volumes, configure basic media and download functions, manage user settings and set quotas, as well as share folders. Unfortunately, we often found ourselves resorting to the Web interface to make even basic changes. The DLNA (Digital Living Network Alliance) server and the download functions, for instance, are both disabled by default and must be enabled from within the plug-in manager, which is only available through the Web interface. The Web interface has an archaic design, but it at least provides the options that are required to get the NAS device fully functional.

iTunes and UPnP server capabilities are offered, and you can stream to DLNA-compatible devices. eDonkey and BitTorrent downloads can be scheduled, and backup options include the Snapshot feature and NAS-to-NAS replication.

The Promise SmartStor NS4600 NAS device was quite fast during our tests. In Intel's NAS Performance Toolkit it performed well in the HD playback and Restore tests, achieving read speeds of 38 megabytes per second and 65.4MBps, respectively. Write-based backup tasks were slightly slower, averaging 27MBps.

With four 1TB Seagate Barracuda 7200.11 drives configured in RAID 0, the NAS device wrote 20GB worth of 3-4GB files at a rate of 35.5MBps, read them at 63.3MBps, and performed a simultaneous read/write task at 19.5MBps. In a small file transfer test — copying 3GB of 1MB individual files — it wrote at 22.5MBps, read at 28.3MBps and performed a simultaneous read/write at 11.9MBps.

Though it looks sleek and is very quick, the Promise SmartStor NS4600 NAS device is let down by poor software. We were also disappointed that we couldn't back up external hard drives.

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