The use of 2.5in notebook drives allows the Synology DS409slim to be smaller than most NAS devices on the market, and it will also consume less power. However, it also means that the maximum storage capacity of the DS409slim isn't as high as NAS devices that use 3.5in drives.
The Synology Disk Station DS409slim has four drive bays, yet retains a small stature that makes it look like a toy. It even comes with a display stand. Nevertheless, it has the same connectivity you would find on larger NAS devices, including eSATA, Gigabit Ethernet and two USB ports. You also get a one-touch copy button that can be used to easily make backups and from external drives.
The Synology Disk Station DS409slim drives are hot-swappable and can be formatted in a number of configurations, including basic (separate drives), JBOD and RAID levels 0, 1, 1+0, 5, 5+Spare and 6.
You will be able to access the Synology Disk Station DS409slim drive from computers running Windows, Mac OS X or Linux, and it can be set up as an FTP server, too.
Media features like UPnP, iTunes and photo servers are available, along with a download station from which you can queue BitTorrent, HTTP, FTP and eMule downloads. Unfortunately there is no way to schedule download times for these.
The Synology Disk Station DS409slim's Disk Manager is similar to QNAP's revamped Firmware 3.0 web interface. It uses an icon-based interface and configuration wizards, which will help people without much experience of network-attached storage.
Like QNAP's TS-219 Turbo NAS, Synology also allows you to expand the Synology Disk Station DS409slim's functionality through third-party Linux packages, which can be installed through the Disk Manager interface. These packages are available to download from the Synology website and allow you to install Web site and network management software, for example.
The Synology Disk Station DS409slim NAS device has a 1.2GHz CPU and 128MB of RAM, and it produces respectable file transfer speeds. For our tests, we installed three solid-state drives - one Intel X25-M 32GB drive and two Solidata 32GB drives - in a RAID 0 configuration. The DS409slim was connected via Gigabit Ethernet to our test computer, which has a 300GB Western Digital VelociRaptor system drive.
The NAS device performed strongly in the Intel NAS Performance Toolkit HD playback test, where it streamed 720p video at an average rate of 71.7 megabytes per second (MBps). It was also able to simultaneously play back and record high-definition footage at a rate of 59.6MBps.
In our own real world file transfer tests, the Synology Disk Station DS409slim wrote 20GB worth of 3-4GB files at a rate of 34.8MBps, read the same data at 57.6MBps, and performed a simultaneous read/write operation at a rate of 22.7MBps. It wrote 3GB worth of 1MB files at a rate of 23.3MBps, read them at 35.7MBps and performed a simultaneous read/write operation at 9.4MBps. These speeds are roughly on par with the similarly powerful two-bay QNAP TS-219 Turbo NAS.
Conventional 2.5in hard drives are quieter than 3.5in drives, and solid-state drives are completely silent. This makes the DS409slim the perfect NAS if you want something that won't make much noise. Power efficiency is also better than other NAS devices. During testing the Disk Station DS409slim (configured with three solid-state drives) consumed 11.5 Watts when idle, and a maximum of 14W when writing data to the drives. By comparison, the two-bay QNAP TS-219 Turbo NAS required 23W when running two 3.5in hard drives.
However, there are still some disadvantages to using 2.5in hard drives. They typically cost more than 3.5in drives at the same capacity - particularly when it comes to solid-state drives - and the DS409slim's total capacity is currently limited 2TB due to smaller individual drive capacities (the current maximum capacity of 2.5in drives is currently 500GB).
Synology's first 2.5in network-attached storage offering has all the features of larger NAS devices in a smaller, power-efficient package. However, the Synology Disk Station DS409slim's cost and capacity limitations are major down sides.