Synology DiskStation DS225+ review

Synology announced the DiskStation DS225+ on 23 July 2025. It is a two-bay NAS that runs Synology's DSM operating system and ships without drives. The box holds the unit, an accessory pack, the power adapter and cord, and two RJ-45 LAN cables.

The hardware is modest. It uses an Intel Celeron J4125, 2 GB of RAM and two SATA bays. The software is the main draw, and owner feedback reflects that split: praise for DSM, complaints about the hardware.

The two hot-swappable bays take 3.5" SATA hard drives or 2.5" SATA SSDs. Synology quotes up to 40 TB raw capacity with 20 TB drives, and a maximum single volume of 108 TB.

There are no M.2 slots. SSD cache works only with selected compatible SATA SSDs in the main bays, so cache drives must go in one of the two bays that would otherwise hold data. There is no PCIe slot and no expansion unit support. The two USB 3.2 Gen 1 ports are the only other connections for storage. Owners list the missing M.2 cache among their recurring complaints.

Volume options include SHR, RAID 0, RAID 1 and JBOD, on Btrfs or ext4.

The Celeron J4125 has four cores and four threads, runs at 2.0 GHz base and 2.7 GHz turbo, and includes a hardware encryption engine. NASCompares describes it as a 2019-era 14nm Gemini Lake Refresh chip. It also recorded 60–70% CPU use under light Surveillance Station or Synology Drive sync work. Several reviewers and owners call the CPU old and slow.

The bigger issue for media users is transcoding. Synology did not enable Quick Sync, so Plex and Jellyfin cannot use hardware transcoding without user-installed drivers. Blackvoid links this to the Linux kernel 5.10 used on all 2025 models and publishes a workaround guide. Owners on SynoForum report conflicting answers from Synology support on the subject. If your Plex library relies on hardware transcoding, plan for that unofficial workaround or look elsewhere.

The unit ships with 2 GB of non-ECC DDR4 and has one slot. Synology lists the maximum as 6 GB, made up of 2 GB plus 4 GB. Synology does not give full warranty or support if non-Synology RAM is used.

That ceiling shapes what the box can run. Virtual Machine Manager is rated for two recommended VMs, plus two Virtual DSM instances with one licence free. Synology Photos object recognition needs at least 4 GB, so the stock 2 GB falls short of that feature's requirement. With one slot and a 6 GB limit, it suits a few light containers better than several VMs. Owners repeatedly flag the small amount of RAM.

There is one 2.5GbE port and one 1GbE port. Owners and reviewers describe the 2.5GbE port as a welcome upgrade. The 1GbE port's maximum packet size (MTU) is 1,500 bytes.

There is no 10GbE port, and Dong Knows Tech states there is no upgrade path for it. truthful.reviews reports that SMB multichannel appeared non-functional in its testing, so combining the two ports for faster single-client SMB transfers may not work.

DSM brings snapshots, Hyper Backup and Synology High Availability. Surveillance Station includes two free camera licences and supports up to 25 cameras, though the CPU figures above suggest keeping camera loads light. Owners praise the software, ease of use and app ecosystem.

Drive support has changed since launch. At launch the DS225+ officially supported only Synology-branded drives. DSM 7.3 restored support for third-party 3.5" and 2.5" SATA hard drives and SSDs, which resolves the main openness complaint for anyone running current firmware. The RAM warranty restriction remains. Synology lists DSM as the operating system and does not list support for others.

Hardware warranty is three years, extendable to five.

The DS225+ is a software-led purchase. Its strengths are DSM's backup and snapshot tools, which owners praise for ease of use, and a 2.5GbE port that owners call a welcome upgrade. The hardware limits what else it can do. The 2019-era CPU, disabled Quick Sync, 6 GB RAM ceiling and lack of M.2 slots rule it out as a transcoding media server or a host for several VMs. Buy it for simple, managed storage on two drives. Beyond one RAM slot that tops out at 6 GB, the specification lists no M.2 slots, no PCIe slot and no expansion unit.