Synology DS425+ NAS, 4 bays, Intel Celeron J4125, 2 GB, 2.5GbE

The four bays take 3.5-inch SATA hard drives and 2.5-inch SATA SSDs, and the manufacturer lists a maximum supported capacity of 80 TB. The bays are hot-swappable and lockable, so a failed drive can be replaced without turning the NAS off. RAID 0, 1, 5, 6, 10 and JBOD are supported, letting you balance capacity against protection.

One 2.5GbE port gives roughly two and a half times the bandwidth of ordinary gigabit, provided your computer or switch supports it as well. The second, 1GbE port acts as a failover link: if one connection drops, the NAS keeps working through the other. According to the manufacturer, sequential reads reach 278 MB/s and writes 281 MB/s.

Two built-in M.2 slots take NVMe SSDs that act as a cache. Frequently used files are served quickly from flash while all four bays remain free for large hard drives. This helps most when several people open the same documents or photo libraries at the same time.

The quad-core Intel Celeron J4125 runs at a 2.0 GHz base clock and boosts up to 2.7 GHz under load. It ships with 2 GB of DDR4 memory; there is one memory slot and the maximum supported amount is 6 GB. This model does not use ECC memory. File versioning helps you quickly restore files that were deleted by accident or damaged by malware.

With two 92 mm fans, the manufacturer rates the noise level at 21.6 dB. Typical power draw is 28.25 W and 6.1 W with the drives in standby, and power comes from an external 90 W adapter. At 199 × 223 × 166 mm and 2.18 kg the NAS fits on a shelf; power and network cables are in the box, and Wake-on-LAN lets you wake it over the network.

Home offices and small teams that want files, backups and shared folders in one place and already run, or plan to move to, a 2.5GbE network; photographers who get faster access to photo libraries thanks to SSD caching; and users who want RAID 5 protection across four hot-swap drives.