Synology DiskStation ds1520+ vs ds1621+

Both of the devices have the same working temperature, and they are equally compatible with various operating systems.

Following are the similarities and differences between these two devices:

  • Ds1621+ has a better processor than its counterpart.
  • The RAM of ds1621 is larger than its peer.
  • Both of the devices have the same maximum single storage volumes.
  • Backup and sharing of ds1621+ is marginally better than its competitor.
  • The interface of 1621+ is better than its rival.
  • The system requirements and the supported browsers of both devices are the same.
  • Noise levels of ds1621+ are higher than ds1520+.
  • Both of the devices have the same warranty period but the warranty of ds1520+ can be further extended.
  • Ds1621 is more expensive than ds1520+.

The Synology DS1520+ is a five-bay cloud storage device that possesses 4 GB DDR non-ECC SODIMM RAM. It has a 2.2 GHz quad-core AMD Ryzen Processor along with a maximum single storage volume of 108 TB.

To procure data from various sources, it uses LAN/WAN, Hybrid RAID, JBOD, RAID 0, RAID 1, RAID 5, RAID 6, and RAID 10.

Its File Transfer Protocols include WebDAV SMB, AFP, NFS, and FTP.

On the flip side, Synology DS1621+ is a six-bay network attached storage (NAS) that also comes with a maximum single storage volume of 108 TB.

It contains 2.0 GHz quad-core Intel Celeron Processor that has the ability to boost up to 2.7 GHz and 8 GB non-ECC DDR RAM (4 GB mounted on board and 4 GB SODIMM).

Moreover, it uses LAN/WAN and same Raid modes as its counterpart, to retrieve data from different sources. Its FTP protocols are also similar to its peer which include SMB, AFP, NFS, FTP, and WebDAV.

Side By Side Comparison:

Synology DS420J

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Synology DS1621+

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Compared to Synology ds1520+, ds1621+ has a more powerful processor, larger RAM, much faster transfer rates, and a higher price tag. While the warranty periods and maximum single storage volumes of both devices are the same.

Contrasting Table

Cloud StorageDiskStation ds1520+DiskStation ds1621+
Processor2.2 GHz quad core AMD Ryzen V1500B2.0GHz quad-core Intel Celeron J4125 (Turbo Boost up to 2.7GHz)
Number of bays6 bays  5 bays


The transfer rates of Synology ds1520+ are much less compared to its peer.

It has sequential read speed of 451.28 MB/s and sequential write speed of 451.18 MB/s.

It has lower transfer rates because it has 4 GB RAM which is lower than its counterpart and a slightly higher frequency processor but without the turbo boost feature.

On the contrary, the read speed of Synology ds1621+ is about 4 times greater than its contender, while its write speed is more than two times faster than its rival.

Its sequential read speed is 2317 MB/s, while its sequential write speed is 1130 MB/s.

Therefore, it clearly has an edge over its rival in this segment.

Cloud StorageDiskStation ds1520+DiskStation ds1621+
Read Speed451.28 MB/s2317 MB/s
Write Speed451.18 MB/s1130 MB/s


The Synology ds1520+ has structure of a mid-sized rectangular shaped tower.

In the front panel, it has a status indicator LED, 4 drive status indicator LEDs, drive tray locks, a USB 3.0 port, and Power button and indicator.

On the back side, it has an eSATA port, power port, 4 GbE RJ-45 port, reset button, 2 system fan, and a Kensington Security Slot.

On the other hand, Synology ds1621+ possesses a more wide mid-sized tower shape.

In the front panel it has a status indicator LED, alert indicator LED, a power button and indicator, LAN indicator LED, 4 drive status indicators LEDs, and drive tray locks.

On the back panel, it has 2 USB 3.1 ports, 2 system fan, a power port, 4 GbE RJ-45 ports, a reset button, 2 PCIe expansion ports, and Kensington Security Slot.

Cloud Storage DevicesDiskStation ds1520+DiskStation ds1621+
Depth (mm)223243
Width (mm)230282
Height (mm)166166
Weight (kg)2.625.1

Maximum Single Storage Volume

Both of these cloud storage devices have equal maximum single storage volume of 108 TB.

Therefore, they can be used to store large volumes of data in a single place which is beneficial in small sized businesses.

Cloud Storage DevicesDiskStation ds1520+DiskStation ds1621+
Maximum single volume storageTB108 TB

System Requirements

Both support the same OS.

Namely, windows 7, windows 8, windows 8.1, windows 10 and windows 11.

In mac, they support mac OS 10.12, OS 10.13, OS 10.14, OS 10.15, OS 11, and OS 12.

Furthermore, they are also compatible with operating systems like Virtual DSM and Linux as well.

Supported Browsers

Both share the same browsers support, which are:

  • All versions Google Chrome
  • All versions of Mozilla Firefox
  • Internet Explorer 10 and onwards
  • Safari 10 and onwards
  • Safari for iOS 10 and onwards (for apple devices)
  • Chrome for Android 6.0 and onwards (android devices)

Backup and sharing

For backup, Synology ds1520+ has Cloud Sync to back up cloud data, Synology Drive Client to back up data on PCs and servers and Hyper Backup to back up data to Synology NAS devices.

While for sharing, it is equipped with Synology Collaboration Suite that contains Synology Drive, Synology Office, Synology MailPlus and Synology Chat.

Contrarily, Synology ds1621+ has Snapshot Replication and Hyper Backup to back up data on Synology NAS and make in-time file versions of the stored data.

It also has Synology Active Backup suit that backs up data on PCs, servers, VMware and Hyper-V VMs and cloud applications.

Moreover, it also has Synology Collaboration Suit that has all the elements of its peer with an extra feature of Synology Calendar.  

Set up

It is very simple and easy to set up both of these Synology DiskStations.

These NAS can be set up by following the steps given ahead:

  • Plug in the power source to the device.
  • Press the start button and the NAS will power on.
  • LED will turn blue after some time.
  • Download and install all the required system software to complete the installation process.

Both of the devices have the same operating temperature from 0 to 40 degree centigrade.


Both of the devices contain two system cooling fans of the same size (92mm x 92mm).

However, the noise level of ds1520+ is 20.8 dB, which is better than its peer that has the noise level of 25.2 dB.

This is because ds1621+ generates more heat that makes the fans spin faster and produces louder noise.   


Both of the devices originally come with a limited warranty of 3 years but the warranty of ds1520+ can be extended to a whole of 5 years.

Therefore, the predecessor takes the lead over its successor in this segment.