Specifications

The DS1515+ uses the same CPU as the DS1815+ and DS415+ from Synology, a Rangeley SoC (C2538, quad-core, 2.4 GHz) that supports the Advanced Encryption Standard New Instructions (AES-NI) technology, but not QuickAssist, which can speed networking and security applications up significantly. As such, we definitely expect to see performance dip with encrypted file transfers.

Synology equipped the NAS with 2 GB of RAM, which might be enough for most applications because DSM isn't RAM intensive; however, we would feel much more comfortable with at least 4 GB or even 8 GB of RAM. The server's memory total would have also been easily upgradable to 8 GB had Synology only used a 4 GB DIMM instead of a 2 GB one. This particular NAS can take up to five HDDs on its own or fifteen with two DX513 expansion units.

The server's CPU supports four 2.5 GbE interfaces, and while other hardware components limit the bandwidth to 1 GbE, the DS1515+ actually utilities four Ethernet ports. However, those aren't provided for by the SoC but a third-party controller (Marvel Alaska 88E1543), which has the NAS support the Link Aggregation Control Protocol (LACP) for a 2 GbE line for every two Ethernet ports. The other I/O ports are comprised of four USB 3.0 and the two eSATA ports to which you can attach compatible Synology expansion units.

Two 80 mm fans keep the NAS cool, and while neither are very quiet with the unit at low utilization, DSM allows you to set their speed to either "quiet" or "cool". The NAS only comes with a two year warranty. We would like to see such an expensive business model come with at least three year. Unfortunately, most NAS manufacturers only offer two years, which needs to change.

The DX513 expansion unit can take up to five HDDs, which makes for 30 TB if you use 6 TB disks. You can manage the unit in DSM, and its only I/O port is an eSATA port that connects to a compatible Synology NAS. Synology's provided data states the unit to consume very little power, which we will confirm in our test sessions, and it, contrary to the DS1515+, comes with a three year warranty. Its cooling is taken care of by two 80 mm fans, so we don't expect it to be whisper quiet. A 80 PLUS certified Seasonic PSU of high quality, the SS-200SU, provides the unit with power.