Synology DiskStation DS1621xs+ review: This Xeon powerhouse does it all

Synology makes the best NAS for home users, but the Taiwanese manufacturer also caters to the SMB and IT categories with its business-focused RackStation and DiskStation xs series. These enclosures tend to offer five-year warranty as standard, feature ECC memory, and are generally designed to handle high I/O workloads.

To that effect, Synology's DS1621xs+ is an exciting release that has the distinction of being the first 6-bay DiskStation model to offer 10GbE networking and a Xeon chipset out of the box. The NAS builds on the DiskStation DS1621+ by offering more memory, built-in PCIe slot for adding 25GbE network interface cards, and better after-sales service.

Synology claims the NAS offers sequential reads of up to 3.1GB/s and writes of 1.8GB/s, putting it in a league of its own. There are a lot of alternatives available if you're looking for a NAS enclosure with 10GbE networking, so let's find out if the DS1621xs+ can hold its own in this category.

Synology DiskStation DS1621xs+ Price and availability

The DiskStation DS1621xs+ in most global markets where Synology has a presence. The NAS retails for $1,600 in the U.S. and £1600 in the UK, and that's just for the enclosure; you will have to pick up hard drives additionally.

The DS1621xs+ offers a five-year warranty as standard, and Synology provides a next-day replacement service should anything go awry with your unit.

Synology DiskStation DS1621xs+ Hardware

The DiskStation DS1621xs+ brings a lot to the table: the Intel Xeon D-1527 is a powerhouse, you get 10GbE out of the box, M.2 caching, and 8GB of memory out of the box. With the ability to add up to 10 additional drives via the dual eSATA ports, you can scale the storage based on your requirements.

As for what's not available, the DS1621xs+ misses out on SHR. Synology notes that as this is a business-focused NAS, it isn't offering the feature as most organizations will plan out their storage needs in advance and buy similar-sized drives. That said, you will find the feature on the standard DS1621+.

Here's the rundown of the hardware on the DS1621xs+:

Synology DiskStation DS1621xs+ Design and features

The DiskStation DS1621xs+ follows the same design language as most of Synology's NAS enclosures, with a metal chassis decked out in a matte finish. As you'd imagine from a product in this category, it has sturdy build quality and plenty of ventilation. The Synology logo at the sides has a perforated design, and you'll find two 92mm fans at the back that make sure the NAS doesn't overheat.

The front is dominated by the six 3.5-inch drive bays that are made out of plastic. There are LED indicators on each drive bay, and you'll also find LEDs for system status, alerts, and LAN ports at the front. The power button is located amidst the LED indicators, and there is a USB 3.0 port on the bottom right.

Round the back, you'll find the two 92mm fans, two Gigabit Ethernet ports that can be used with Link Aggregation, and a 10GbE networking port that's clearly labeled. This isn't the first DiskStation with 10GbE networking; the DS1817 had two 10 Gigabit ports alongside two Gigabit ports, but that model was lacking in power. With a Broadwell-based Xeon under the hood, that's not an issue with the DS1621xs+.

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There are two eSATA ports as well, giving you the ability to add two DX517 expansion units to increase the overall drives to 16. While that is a nice addition, it would have been ideal if the unit had expansion ports for the 12-bay DX1215 as that fits in better with the product positioning of this NAS.

You'll find two USB 3.0 ports at the back, and there's a PCIe slot to the right that lets you add network interface cards. The DS1621xs+ has dual M.2 2280 slots for SSD caching, and they're located within the chassis to the left of the drive bays. You'll find the SO-DIMM memory slots at the bottom, with the DS1621xs+ coming with 8GB of 2666MHz ECC DDR4 memory out of the box.

There's an additional memory slot available if you want to add more memory down the line, with a maximum of 32GB allowed. You'll have to use Synology-branded RAM when you're upgrading; using aftermarket memory is likely to invalidate the unit's warranty.

As is the case with most Synology models, the drive bays let you slot in the 3.5-inch drives without any tools. You will need to mount 2.5-inch drives to the bays with screws, and these are provided with the packaging. Synology also furnishes keys that lets you lock the drive bays, and two Cat5e Ethernet cables.

Like the standard DS1621+, the DS1621xs+ features an internal PSU, so you just get a power cable in the box. I'm fine with this move as it means there's a less chance of the cable being knocked loose — as was the case on the DS1520+ more than once.

Synology DiskStation DS1621xs+ Performance

The DiskStation DS1621xs+ is catered to businesses, and comes with a range of utilities in the DSM software for running virtual machines and backing up data. Active Backup for Business is a centralized hub that lets you back up PCs, file servers, and virtual machines effortlessly. You'll also find Active Backup for Microsoft 365 and Google Workspace, offering an easy way to retain data on-site.

The quad-core 2.2GHz Intel Xeon D-1527 delivers more than enough performance, and is ideally suited for running VMs or collaborative office software like Synology Drive that is file-intensive. I tested the NAS with Synology's 8TB HAT5300 drives; these drives are made by Toshiba but feature custom firmware that delivers better performance in a NAS system.

Combined with the HAT5300, the DS1621xs+ delivered superlative performance in just about all workloads. File transfers were 5 to 12% faster than what I got with the IronWolf Pro on the DS1621+, there were zero issues with backing up data from four machines at once, and while not aimed at multimedia playback, the NAS held its own in this regard.

I used the DS1621xs+ alongside the DS1621+, and while there isn't a huge performance delta between the two, the 10GbE networking by itself is a differentiator. There's a case to be made that the storage could end up being the bottleneck here, and while the NAS has two M.2 slots, they're only used for caching.

Synology has clarified that it doesn't offer M.2 storage on its NAS enclosures because of overheating issues, and while you will see a noticeable gain in file-intensive workloads with SSD caching, it would be great if Synology figured out a solution for the heating issues and allowed M.2 slots to be used for storage.

As for power usage, the DS1621xs+ is hungrier than the standard model, and that's down to the 35W Xeon platform. And although the DSM 7.0 update is now available for over forty enclosures, the DS1621xs+ is still on DSM 6.2. Because the NAS is essentially categorized as a business-focused model, Synology is taking a little more time rolling out the update.

Synology is far and above in the lead when it comes to NAS software, and DSM 7.0 extends that lead. There are exciting additions to SSD caching, and new features like Hybrid Share make it easier for businesses to manage data across various locations. There are much-needed security fixes in DSM 7.0 as well, and while there's no word on when the update will roll out to the DS1621xs+, it shouldn't be too long.

Synology DiskStation DS1621xs+ The competition

The DS1621xs+ stands out for the fact that it offers 10GbE networking out of the box, but it isn't the only NAS enclosure in the market to do so. QNAP's TS-832PX-4G is a new addition that comes with an exhaustive feature-set, including two 10 Gigabit Ethernet ports, two 2.5 Gigabit ports, 4GB of RAM out of the box, and a quad-core ARM Cortex A57 chipset. While the 832PX doesn't have quite the same power as the DS1621xs+, at $879, you get a lot for your money.

If you're in the market for value, TerraMaster's F2-422 is the most affordable NAS with 10GbE networking. The 2-bay enclosure retails for $380, and TerraMaster also sells a 5-bay variant in the same series (F5-422) for $600, and the 8-bay F8-422 for $1,300. All three models are powered by an Intel Apollo J3455 chipset with 4GB of RAM, and natively handle 4K Plex transcoding.

If you're okay with missing out on 10GbE and plan to add it later via an NIC, the DiskStation DS1621+ is a fantastic alternative. The 6-bay Ryzen-powered NAS holds its own in day-to-day workloads, comes with 4GB of memory out of the box, and at $800, it's half the cost of the DS1621xs+.

Synology DiskStation DS1621xs+ Should you buy?

You should buy this if ...

You're looking for 10GbE networking

Synology fans have been asking for 10GbE networking in the DiskStation series for some time now, and the brand has delivered with the DS1621xs+.

You want a NAS with incredible performance

The Xeon D-1527 delivers standout performance for I/O intensive workloads, making it an obvious choice for businesses looking to switch to an all-in-one solution for backing up data, collaborative office software, and running several virtual machines at once.

You need a scalable NAS

The DS1621xs+ lets you easily extend the memory, add more drives via the eSATA ports, and an additional networking card that unlocks 25GbE connectivity. So if you require these upgrades down the line, you need to pick up the DS1621xs+.

You should not buy this if ...

You're looking for a NAS for home use

The DS1621xs+ is aimed squarely at businesses, and while the feature-set is enticing, the DS1621+ offers a lot of the same features at half the cost.

With the DiskStation DS1621xs+, Synology is delivering a desktop enclosure that has a lot of the same features as its RackStation models. The Xeon D-1527 offers more than enough power for intensive workloads, 10GbE networking is a great addition, and 8GB of RAM is useful for running VMs. You can easily add more memory, an NIC for an additional 10GbE or even 25GbE port, and increase the number of drive bays to 16 via the two eSATA ports.

4 out of 5

That said, the NAS does cost a significant premium over the standard DS1621+. You are getting 10GbE networking out of the box, double the memory, and better after-sales service, but if you don't care too much about those additions and plan to use the PCIe slot on the DS1621+ to add a 10GbE card, you stand to save a lot of cash.

Synology DiskStation DS1621xs+

Bottom line: The DiskStation DS1621xs+ delivers incredible performance thanks to a Xeon chipset, and it offers 10 Gigabit networking out of the box. With 8GB of memory, M.2 slots for caching, six drive bays that can hold a total of 96TB of storage, and an exhaustive suite of software features, the DS1621xs+ is an outstanding option for businesses and enthusiasts setting up a homelab.

• $1,599 at Amazon
• $1,600 at Newegg
• $1,600 at B&H Photo