The DS920+ is an affordable NAS for the power user, capable of breezing through 4K video transcodes, running virtual machines, and Docker containers. The only disappointment is the lack of 2.5Gb Ethernet connectivity.  

It’s available without drives for around $550. Join us as we take a closer look at what makes the DS920+ the best NAS for the pro user.

DS920+ Specifications and Design

The Synology DS920+ is superficially identical to all the recent four-bay Synology devices, with a sleek black plastic exterior and distinctive bevel on all edges. Measuring 8.73 x 7.83 x 6.54 inches (223 x 199 x 166mm), it weighs 5lbs (2.25kg) without drives fitted.

Around the rear, you’ll find dual Gigabit Ethernet ports, a USB3.0 port, and an eSATA connection. You’ll probably want to save the USB port for use with an uninterruptible power supply. There’s another USB3.0 port on the front of the device, useful for quickly plugging in an external disk that you need to pull files from.

The DS920+ uses the same toolless disk caddies that make fitting drives a breeze. But scratch beneath the surface and you’ll find a few key differences to other models in the line-up.

Firstly, the internals. Fitted with a powerful quad-core 2GHz J4125 Intel Celeron CPU and 4GB of RAM, the 920+ can handle hardware transcoding of 4K video files, has virtualization support, and provides an AES-NI encryption engine for great performance when using secure folders. Synology states photo indexation as 25% faster than the previous generation DS918+ model.

Secondly, there’s a lot of upgrade potential here for when you need to scale up.

On the underside of the device you’ll find two m.2 SSD slots for NVMe caching drives. These can be used to significantly speed up random file operations.

Remove the drives and there’s a single SO-DIMM memory upgrade slot tucked away just inside on the right. This can officially support up to a 4GB SO-DIMM module, which would give a total system memory potential of 8GB, and it’s an inexpensive upgrade. I say “officially support” because many users have found higher memory modules are also recognized. The CPU lists 8GB as the maximum though, so anything beyond this may cause errors later down the line and isn’t worth the risk; nor will Synology be able to support you if something goes wrong.

An eSATA port allows for connection to a drive expansion unit, such as the five-bay DX517. This adds potentially 80TB more. However, if you know you’ll likely need more drives in the short term (and can afford it), purchasing a system with more built-in drive slots is always a better choice. The Synology NAS selector tool can help there. For most people, four bays is a good compromise. It allows for secure fault tolerance of a single disk, while still letting you take advantage of mixed drive sizes in a flexible Synology Hybrid RAID configuration.

Setting Up the DS920+

As with all of Synology’s line-up, hardware installation and system setup are user-friendly and easy.

Starting with the hardware, you don’t need any tools to install drives. Just pull out the drives, and pull off the plastic clips at the side. Slot the drive in, then push back the clips, and re-insert.

Once you’ve powered on the system, give it a moment, then navigate to find.synology.com from any desktop browser. This should find your new NAS, and you’ll be guided through the initial set up. From there, you’ll be greeted by the DiskStation Manager OS. It’s a familiar-looking graphical environment that anyone who used Windows or Mac will feel at home with. You even get a start button in the top left.

Your first step should be to create a storage volume, which you can do using a helpful wizard after launching the Storage Manager. If you’re new to Synology, or Networked Attached Storage in general, it’s worth taking a moment to explain the Synology Hybrid RAID technology.

Synology Hybrid RAID

Hard drives can and do fail, and one of the biggest reasons to use a storage system with two or more drives is to allow for redundancy; that is, a drive can fail, and you won’t lose any data. This called a Redundant Array of Inexpensive Disks (or RAID, for short). Different types of RAID exist, but the one we’re usually concerned with is RAID5, in which data blocks are spread across the disks, as well as a parity block. The parity block lets you recover data if any of the actual data blocks are lost.

With standard RAID levels, you need to use disks that are all the same size. This makes it expensive to start, and inflexible when it comes to upgrading. While you can swap out a drive for a larger one, the additional space will be of no benefit. The key difference is that Synology Hybrid RAID offers the same one disk fault tolerance (or two, if you’re particularly risk-averse), but you can mix and match drive sizes. Regardless of what disks you’re working with, the Synology software will intelligently optimize your array to use your available space most efficiently. Use the RAID calculator to estimate how much more space you’d get in an SHR configuration compared to standard RAID level.

Adding or upgrading a drive is also simple: the only rule is that the drive should be at least as big as the largest drive currently installed in the system. This makes upgrading your storage very budget-friendly.

Once you’ve created your storage volume, you can begin setting up shared folders from the Control Panel, and install software packages from Package Center.

Virtual Machine and Docker Support

There’s a huge range of first and third-party software available, including the incredible Synology Moments, a local photo management solution that offers AI image analysis similar to Google Photos. One quick note is that if you’re planning to install Plex, it’s best to do so by downloading the latest version directly from Plex, and using the manual install process. The version on Synology Package Center lags behind.

In addition, both Synology’s own Virtual Machine Manager hypervisor software and Docker are officially supported on the Plus series, opening up even more virtualized server systems to run on your home NAS.

Virtual Machine Manager works with a variety of operating systems—even Windows 10—so if you need a secure test environment for some software you’re unsure of, you can simply boot it in a safely contained VM, all from within your browser. Of course, you won’t be gaming on this or replacing your regular desktop anytime soon, but it’s still useful to have a virtual machine running through a web browser anywhere on your network. Just add the ISO, spin up a new instance, and walk through the usual install process.

Docker is another beast entirely, and far too broad of a topic to delve into in this review if you’re unfamiliar. Learn more about Docker in our guide, but the one-sentence summary would be: a Docker image is a virtual application that runs within a completely safe and sandboxed container. All you need to do is set some variables, point it to a data directory, and boot it up. Docker containers don’t run an entire operating system, so they use significantly less memory than a full Virtual Machine. While you can typically run a single virtual machine at a time, you can have tens of Docker containers running 24/7 without impacting the performance of your system.

The range of Docker containers available is immense. If you’ve ever thought “wouldn’t it be cool to run a whatever server at home?”, chance are someone has made a Docker image already.

For instance, I had a Dockerized instance of Pi-Hole set up in ten minutes. It’s a DNS server with built-in ad-blocking, originally designed to run on a Raspberry Pi. It was trivial to install and uses a minimal amount of memory, requiring only the creation of a few data directories and passing in some variables.

If you’re looking at upgrading your home Wi-Fi to a Unifi enterprise system, you might be frustrated at the prospect of having to plug in a hardware dongle to act as the network controller. You’ll be pleased to know that a Dockerized Unifi controller can be used instead.

Performance

Official performance figures for the DS920+ put total file throughput available at around 225MB/s read and slightly lower writer speeds, but this is when using the dual-Gigabit Ethernet ports in a link-aggregated configuration. In reality, this means any single Gigabit client device will achieve around 100 to 115MB/s, which our real-world tests confirmed.

Using faster drives will not improve this, and if you’re on Wi-Fi rather than a wired Gigabit Ethernet connection, you may get even slower speeds. Ultimately, your network (and the Gigabit ports on the DS920+) are the limiting factor here when it comes to the performance of file access over the network—not the CPU, RAM, or speed of the drives you put in it.

NVMe Caching

One of the standout upgrade options on the 920+ is the two NVMe drive slots on the underside of the device. NVMe is a new generation of Solid State Drive (SSD) that looks a bit like a memory stick. But don’t confuse their existence as yet another place to add storage drives to. The m.2 NVMe slots are limited to use as a caching system, and cannot be used to expand a storage volume.

A single NVMe drive allows you to create a read-only cache, while a pair of drives can be used for read-write caching. This creates a RAID1 array of SSDs to ensure there are no data errors in data being written back to your storage array from the cache.

We should note however that not everything you do on a NAS will benefit from NVMe caching. Specifically, it won’t help with large sequential read/write operations, which are one of the main uses of a NAS. This also means it won’t help with serving up video files for a Plex server. What they will help with is random read/write operations, such as those in a virtual machine, database, or other server package running on the NAS.

For this reason, it’s difficult to measure actual performance gains from NVMe caching: simply copying files to and from the device would show no difference. Instead, if you have an SSD-cache capable device, I’d recommend opening up the Storage Manager -> SSD Cache -> SSD Cache Advisor to see if you might benefit, and what size cache drive is recommended.

There are a few other things you should know about using an SSD cache.

First, don’t remove the hardware without removing the cache from the volume first, even when the device is powered off. There’s a warning message if you power off from DSM to remind you of this.

Second, NVMe drives are quite pricey, and considered consumables. The error rate on SSDs increases with age and usage, though DiskStation Manager will warn you when the drives are degraded. Synology’s own SNV3400 NVMe drive that we used for testing are rated to 500TBW (TeraBytes Written), which is well above the industry average. While you can fit cheaper NVMe drives from competitors, they will need to be replaced more quickly, or may result in data corruption.

Lastly, caching systems use memory too. This works out to around 50MB for a 128GB SSD.

Should You Buy The DS920+?

The DS920+ is the best, affordable, scaleable NAS for the professional home user that values their data. It’s a beast of a machine that will handle everything you throw at it with ease—whether that’s running your own server software via Docker containers, handling your home security via Surveillance Station, or keeping decades of family photos safe in Synology Moments. Most importantly, it’ll do so within the Synology ecosystem. That means easy-to-use software, reliable hardware, and excellent support if you need it. In fact, Synology guarantees their Plus series devices for three years, compared to two years for other models. In addition, software updates are usually provided for seven years.

Synology isn’t the cheapest NAS manufacturer out there. You could certainly get faster hardware at a similar price point elsewhere, but you wouldn’t benefit from any of the exclusive technologies such as Synology Hybrid RAID that makes efficient use of mixed disk sizes, nor the fantastic range of first-party software. You could even roll your own budget NAS with open-source software like FreeNAS or unRAID, but I wouldn’t recommend putting anything too important on there. I’ve trusted Synology with my data for many years now, and it’s never let me down.

The only real disappointment with the hardware is the lack of Multi-Gigabit Ethernet connectivity. While link-aggregated dual-Gigabit connection means you can have full Gigabit performance to multiple clients, it doesn’t help to speed up performance to any single client. This matters if you want to use your NAS for video editing, and we may find multi-gig LAN connections more common in the coming years. For typical users though, Gigabit connectivity is plenty fast enough for things like streaming 4K video.

What Exactly Can You Do with a Synology NAS?

More broadly speaking, you might be wondering what you can actually do with a Network Attached Storage system. A Synology NAS has always been a central part of my home network, and it’s one of a few devices that I’d class as essential to my work and family life.

Backup

Synology NAS can be a central point of backup for everything in your home, whether that’s your family photos spread across multiple smartphones, that Windows folder with all those important documents, or a Mac OS Time Machine archive.

If you don’t have a backup, then you haven’t experienced data loss (yet)—it’s only a matter of time. Of course, a NAS shouldn’t be your only backup point, but if you have a friend or family member with their own NAS too, you can act as an off-site backup point for each other! Synology makes this easy to set up with HyperBackup.

It’s not just backups either. Synology Drive can keep files in sync across your devices, so you always have the latest copy of a file to work with.

Shared Folders and Media Management

Having a shared folder or two makes your digital home life a lot easier—I can’t remember the last time I had to transfer some files using a USB disk! But this is especially true if you have a large archive of media. Plex is the best media management software around, and it runs natively on a Synology NAS. It’ll let you keep all your media files in one place, then play them anywhere with a single unified and rich interface.

Those looking to move away from Google Photos after the recent pricing and policy changes will be delighted to hear about Synology Moments. Offering easy import of photos from your smartphone, browser, or existing photo archive, Moments takes advantage of the fast CPU in the DS920+ to perform AI analysis of your photos. It automatically identifies people and subjects so you can easily browse and locate those special memories.

Your Own Server

Fancy running your own web development server? Perhaps a Calibre server to automatically convert all your eBooks? PiHole to block all ads at a network level? Surveillance Station to record from your IP security cameras?! With hundreds of native software packages and even more available through Docker, the DS920+ can run it all.

Energy Efficiency

The other benefit of running a NAS as opposed to using a spare computer is that of power consumption. Peaking at less than 40W of power, the DS920+ manages to do an awful lot with very little energy impact. This means you can leave it running all day, ready for when you need it and working away in the background to keep your data safe.