Today, Synology announced the official US availability(*) of its first model year 2025 NAS server, the DiskStation DS925+. The new server is more than just a typical incremental upgrade to the previous DS923+, in the sense that it may not even be an upgrade at all.
To put it differently, the new DS925+ is arguably the most significant hardware release in the entire history of Synology’s Plus (+) server lineup, though not necessarily in a good way.
Let’s find out more.
Synology DS925+: Beyond the regular bi-annual release
As the name suggests, the DS925+ is a four-bay server of model year 2025 designed to hold four internal disks—3.5/2.5-inch hard drives (HDDs) or 2.5-inch solid-state drives (SSDs). After that, the plus (+) notation indicates that it can host an expansion unit.
Unlike previous Plus models that use the old-school eSATA port to host an expansion unit, such as the DX517, the DS925+ is the first to utilize a USB-C expansion port designed to work with the all-new DX525, which was also announced today. With it, the new server can house up to 9 internal SATA drives.
And these internal drives are where things get complicated. That’s because, starting with the 2025 model year, Synology Plus NAS servers will require Synology-branded storage to function correctly.
So, what’s the deal with the new requirement exactly?
What’s the deal with Synology’s new storage requirement?
In reviewing the DS923+, I lamented the fact that it required Synology-branded NVMe SSDs for storage space—third-party NVMe SSDs can only be used as cache. Still, like previous models, the DS923+ supports third-party SATA hard drives and SSDS, albeit sometimes with a one-time “incompatible” warning message for specific models.
As if that weren’t bad enough, with the DS925+, Synology has taken a significant step further by requiring Synology-branded drives throughout its 2025 Plus lineup. Here’s what the company has informed me on this front:
“With the launch of the new Synology 25 Plus series product lineup, Synology is introducing a streamlined compatibility policy designed to enhance reliability and improve user experience. Synology-branded drives will be needed for use in the newly announced Plus series, with plans to update the Product Compatibility List as additional drives can be thoroughly vetted in Synology systems.
This decision reflects Synology’s ongoing commitment to deliver the highest levels of system stability and performance. Extensive internal testing has shown that drives that follow a rigorous validation process when paired with Synology systems are at less risk of drive failure and ongoing compatibility issues.
Additionally, Synology will be introducing a carefully curated drive compatibility framework for those wanting to integrate third-party drives into their Synology systems. Users can submit drives for a comprehensive testing and documentation process. Drives that meet Synology’s stringent standards may be validated for use, offering flexibility while maintaining system integrity.
It is important to note that existing Synology products released prior to the ’25 series will continue to support third-party drives in accordance with current compatibility guidelines, and this change does not affect J and Values Series models. Additionally, users will be able to migrate older drives from previous Synology models into the new ’25 models, ensuring that their data is still accessible and protected.“
To sum it up, starting with model year 2025, all Synology Plus servers will require Synology-approved hard drives, which are currently those coming from Synology. When asked if there were any third-party drives on the approved list, a Synology representative informed me that there were none “for now.”
It’s unclear what will happen when non-approved drives, namely all third-party drives, are installed in a 2025 Plus server. Will they be recognized at all? If so, will they function to some extent, or will they be ignored altogether?
For years, Synology has maintained a compatible list of drives for each model. However, the one-time “incompatible” warning message during the drive initialization process is often the only immediate consequence when users stray from these lists.
By the way, Synology’s new drive compatibility policy applies only to the Plus tier. Standard and lower-tier servers, such as the J or SE, are not affected, at least for the time being.
Here’s the confusing part: 2025 (and newer) Plus servers can work with third-party drives as long as you don’t initialize the drives with them. Specifically, according to Synology, if you currently have a 2024 model year or older server using third-party storage, you can migrate its drives to a 2025 model, and they will be grandfathered in and continue to function normally.
On this front, there’s nothing to stop users from keeping an old server for the purpose of getting third-party drives “qualified,” though the process can be a hassle. Come to think of it, this artificial restriction may be the reason why the new DS925+ requires a new expansion unit, as the DX517 lacks the mechanism to deny generic storage.
In any case, this type of “compatibility” seems deliberate and self-serving. It’s also controversial since Synology-branded drives are often noticeably more expensive and less readily available than third-party drives from reputable vendors, such as Seagate or Western Digital.
Additionally, Synology doesn’t make hard drives or SSDs. Instead, it utilizes third-party drives, rebrands them with its logo, and applies proprietary firmware so that they are, among other things, “approved”.
Apart from the new storage requirements, the DS925+ is hardware-wise very similar to its predecessor, which shares the same physical shape. The table below shows the hardware specs of the two.
Synoloyg DS925+ vs. DS923+: Hardware specifications
|
 |
|
|---|---|---|
| Synology DS925+ | Synology DS923+ | |
| CPU | AMD Ryzen V1500B Quad-core 2.2 GHz, 4 Cores / 8 Threads |
AMD Ryzen R1600 Dual-core 2.6GHz / 3.1 GHz (turbo), 2 Cores / 4 Threads |
| System Memory | 1x 4 GB DDR4 ECC SODIMM (installed in one of the two memory slots) |
|
| Max Memory | 32GB (16GB x 2) | |
| Dimensions | 6.53 x 7.83 x 8.78 in (166 x 199 x 223 mm) |
|
| Weight | 4.98 lbs (2.26 kg) |
4.93 lbs (2.24 kg) |
| Drive Bays | 4 | |
| Expansion Support | Yes (1x USB-C-based DX525) |
Yes (1x eSATA-based DX517 ) |
| Drive Interface |
SATA 6Gbps/3Gbps (hot-swappable) |
|
| Built-in M.2 Slots (NVMe) |
Two | |
| Drive Support | 3.5″ SATA HDD 2.5″ SATA SSD/HDD M.2 2280 NVMe SSD (cache & storage) |
|
| RAID Types | Hybrid RAID (SHR), Basic, JBOD, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10 |
|
| Max Volume Size | 200TB (with 32GB of RAM), 108TB |
108TB |
| Max Internal Volume Number | 32 | 64 |
| Max SMB Connections | 40 | 30 |
| Max Shared Folder Sync Tasks | 8 | 4 |
| Max Synology Chat Users | 150 | 100 |
| Max Synology Drive / Office Users | 80 | 50 |
| VPN Server – Max Connections | 8 | 4 |
| Max IP Cameras Support (two licenses included for non-Synology cameras) |
40 | |
| Ports | 2x RJ-45 2.5GbE LAN, 2x USB Gen 1 ports, 1x USB-C port (for expansion) |
2x RJ-45 1GbE LAN, 2x USB Gen 1 ports, 1x eSATA port (for expansion) |
| Expansion Slot | None | Network Upgrade Slot |
| Add-on Card (not included) |
None | 10GbE E10G22-T1-Mini module |
| DiskStation Manager (operating system) |
DSM 7 | |
| File System | Internal: Btrfs, EXT4 External: Btrfs, EXT4, EXT3, FAT, NTFS, HFS+, exFAT |
|
| Supported Drives | 3.5″ SATA HDD 2.5″ SATA SSD/HDD M.2 2280 NVMe SSD (cache & storage) |
Standard SATA SSDs and HDDs, standard NVMe SSDs (cache only), Enterprise Series M.2 2280 NVMe SSD: SNV3400 Series (cache and storage) |
| US Launch Price (Compare street prices!) |
$700 | $600 |
| Warranty | 3 years | |
Synology DS925+: Not entirely an upgrade
As you can see from the table, the new DS925+ is not a significant upgrade from the previous DS923+ model. In fact, it can be a slight downgrade in certain aspects.
The two share similar processing power, though the new server has a slightly more powerful (though older) CPU. In terms of network ports, the DS925+ now features two 2.5Gbps ports, a significant upgrade from the two Gigabit ports of the previous model.
On this front, Synology says, “the DS925+ delivers substantial performance gains with preconfigured settings compared to its predecessor, including 149% faster SMB downloads, 150% faster uploads, 131% faster reads, and 150% faster writes.”
While that might be true with default hardware specifications, it’s worth noting that the DS923+ has the option to upgrade to 10Gbps via the E10G22-T1-Mini add-on module, whereas the new server is limited to 2.5Gbps (or 5Gbps if link aggregation is possible), as it has no upgrade option for network connectivity.
Considering the new drive restriction and the added cost of Synology-branded storage, it’s clear that the DS923+ can offer a better total cost of ownership with a superior performance experience. That’s because when you opt for inexpensive third-party hard drives, the savings can easily offset the $110 extra you’d need to spend on the 10Gbps upgrade. And then you’ll get a 10Gbps-capable server, which will be much faster than a 2.5Gbps-grade counterpart.
Finally, while the move from eSATA to USB-C for the expansion port is sensible from a design perspective, it does not result in any performance improvement. In fact, it can be worse, since, according to Synology, this port features the USB 3.2 Gen 1 (USB 3.0), which has a ceiling speed of 5 Gbps, compared to 6 Gbps for eSATA.
So, the new DS925+ server will not perform better when hosting an expansion unit than any previous plus NAS models. In reality, chances are it will be worse since USB 3.0 is not as fast or as reliable as eSATA.
A familiar Synology experience
In addition to the differences mentioned above in terms of hardware specifications and related capabilities, running DSM7, the DS925+ remains a family plus server and is expected to deliver the same experience as the DS923+, or nearly any other Synology server.
You can expect a lot of advanced features and functionalities from it via different software packages, including the ability to run virtual machines (VM Manager), comprehensive PC-less downloads (Download Station), a robust media streaming server (Video Station), a security system (Surveillance Station), a personal cloud storage server (Synology Drive Server), and much more.
Availability and pricing
The new Synology DiskStation DS925+ has been available in Asia and the EU/UK since late April. In the US, it’s available today with the suggested retail price of $639.99 (diskless), though the street price will vary.
I’m planning to get a unit to put it through its paces. Check back to see how its real-world performance and, most importantly, the new storage requirement pan out.
