Synology DiskStation DS1520+ Review


When Synology launched its 5-bay DS1019+ last year it was a big disappointment as apart from an extra drive bay, it offered no significant improvements over the DS918+ it replaced. Enter the DS1520+ which aims to rectify all these oversights with a more powerful hardware package and a few extra features.

Out goes the aging quad-core 1.5GHz Intel Celeron J3455 from the DS1019+ and in comes a 2GHz quad-core Celeron J4125 which incorporates an Intel UHD 600 Graphics chip for smooth 4K video streaming. Memory sees big improvements too, as the slow DDR3L that hampered the DS1019+ is replaced by 8GB of faster DDR4.

The port count sees a doubling with the DS1520+ sporting four Gigabit ports although yet again, Synology is avoiding the demand from small businesses for a multi-Gigabit option. Storage expansion sees more improvements as the pair of eSATA ports at the rear support Synology’s 5-bay DX517 expansion unit allowing the drive count to be pushed to 15 – hence the ’15’ in the model name.

A feature common to all of Synology’s higher-end Plus models is the pair of M.2 NVMe SSD slots that can be used as a high performance cache. The appliance also offers USB 3 ports fore and aft – the same as the DS1019+.

DS1520+ Build quality

From the front, you’d be hard pushed to spot any differences between the DS1019+ and DS1520+ as they’re both clothed in the same charcoal-black plastic chassis. You get a row of LEDs down the side showing the status of the appliance and all drive bays while below is a USB 3 port and power button.

Tool-free carriers are provided for easy drive installation and they all have mounting holes for fitting SFF SSDs. At the rear you have a connector for the external power supply block while cooling is handled by dual 9cms fans which we found to be exceedingly quiet.

Synology DSM Software on the DS1520+

Synology’s DSM software provides great private cloud and data protection features

The M.2 SSD slots are located underneath the chassis behind removable hatches. Note that these can only be used as a read or read/write cache and not as a storage pool and lower-cost M.2 SATA SSDs aren’t supported either.

The DS1520+ doesn’t have an expansion slot so multi-Gig and 10GbE upgrades are off the table. If you want this feature, we suggest the Simply.Reviews Recommended 6-bay DS1618+ which only costs around $90 more or wait to see our review of the new DS1621xs+ which promises embedded 10GbE as well as an expansion slot.

Collaboration apps

Synology Office Apps for DS1520+

The Synology Office apps are presented as a free alternative to Office 365

Synology’s DSM software has plenty to offer home workers and small businesses as it’s packed with a wealth of productivity apps and data backup tools. The Synology Office app suite is offered as a free alternative to Office 365 and provides a central location for users to create documents, spreadsheets and presentations, collaborate on them together with others and keep them secure.

It works with the Drive app where you create Team folders and decide who else can access them. Regular Office documents can be uploaded and worked on within the app’s browser interface and links to them sent to other users where they can edit the same document so all users see the changes in real time.

Synology Chat Service

Team members and colleagues can quickly message each other using the secure Chat service and client apps

You can do more with the Drive app as it offers a range of Dropbox-like file synchronization services. Management is carried out from the separate Drive Admin Console app while users download the Drive agent for two-way folder syncing on Windows workstations or iOS and Android mobiles.

You can avoid lengthy email communications as loading the Chat apps allow users to have secure, real-time conversations with colleagues whilst working on the same Office documents. The Chat Server Admin app is used to create public and private encrypted messaging channels and along with the Chat web client, Synology provides apps for Windows, iOS and Android

DS1520+ Gigabit NAS and IP SAN performance

For performance testing, we loaded four 14TB Western Digital Red Plus drives and used DSM’s Storage Manager to create a large RAID5 storage pool. With a share mapped over Gigabit to a Xeon Scalable Windows tower server, Iometer reported solid sequential read and write speeds of 113MB/sec and 112MB/sec.

Real world performance was equally good with copies of a 25GB test file delivering sustained read and write rates both of 113MB/sec. Our general backup test saw a 22.4GB test folder with 10,500 small files secured to the share at a speedy 83MB/sec.

IP SAN performance won’t disappoint with a 1TB iSCSI target returning sequential Iometer rates of 113MB/sec and 112MB/sec for read and write operations. Pushing the appliance harder with a dual Gigabit MPIO link to the target saw these increase nicely to 227MB/sec and 221MB/sec.

If you’re planning on using an NVMe SSDs cache, you will only see significant improvement with apps that use random write operations – such as databases and photo indexing tasks. To test this, we installed two 480GB Kingston DC1000B enterprise-class NVMe SSDs and assigned them as a read/write cache to all shares and iSCSI LUNs.

Without caching, we recorded random write speeds of 48MB/sec for our NAS share and with the cache applied, this jumped up to 98MB/sec. I/O throughput for random writes also saw big improvements with the cache increasing them from 1,250 IOPS to 22,600 IOPS.

We saw the same impact on IP SANs with our MPIO link returning un-cached random write speeds of 49MB/sec and 168MB/sec with the cache. Again, I/O throughout received a helping hand with the cache boosting this from 1,480 IOPS to 30,570 IOPS.

Synology DS1520+
Capacity-scalable NAS with SSD Cache Acceleration Capability
Synology DiskStation DS1520+ Review


The more powerful CPU and faster DDR4 memory makes the DS1520+ vastly superior to the DS1019+ it is replacing. It’s disappointing that Synology still won’t implement multi-Gigabit ports but at least you get four Gigabit ports to play with and its NVMe SSD slots can provide a significant boost to random write operations.

Overall, we found the DS1520+ delivers good overall NAS and IP SAN performance and with Synology’s DSM software at the helm, offers a veritable feast of apps including some useful collaboration tools. Small businesses and home offices that want an affordable high capacity storage solution with room to grow will find the DS1520+ a worthy choice.

8.5 Total Score
Worthy Choice for SMB and SOHO Users

Overall, we found the DS1520+ delivers good overall NAS and IP SAN performance and with Synology’s DSM software at the helm, offers a veritable feast of apps including some useful collaboration tools. Small businesses and home offices that want an affordable high capacity storage solution with room to grow will find the DS1520+ a worthy choice.

Build quality
  • Good NAS and IP SAN speeds
  • Feature packed DSM software
  • High storage expansion potential
  • Quad Gigabit ports
  • Very quiet
  • No multi-Gigabit ports
  • Lacking an expansion slot
  • NVMe SSDs only support caching

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