Synology DiskStation DS423+ 4-Bay NAS Enclosure (Diskless, Intel Celeron J4125, 2GB DDR4) Review

The Synology DiskStation DS423+ is built around an Intel Celeron J4125 quad-core processor running at 2.0GHz base with a 2.7GHz burst, paired with 2GB of DDR4 memory in the base diskless configuration. That hardware profile puts it squarely in the prosumer home and small office category, the kind of device that handles multi-user file sharing, automated backups, and light media serving without breaking a sweat, but also without blowing the ceiling off performance expectations. At $2,199 in the pre-loaded 16TB configuration (4x4TB SATA SSD plus dual 500GB M.2 NVMe), this is not an impulse buy. Here is what the specs and verified benchmarks actually tell you about whether it earns that price.

Specs Analysis

The J4125 is the same Gemini Lake Refresh silicon Synology has leaned on across several product generations. It is a known quantity: Intel’s published TDP sits at 10 watts, and it handles AES-NI hardware encryption natively, which matters for anyone running encrypted shared folders or connecting via VPN. The CPU is not a speed demon by 2024 standards, but for NAS workloads including transcoding low-bitrate files, running Synology’s Surveillance Station with a handful of cameras, or serving files to a dozen concurrent users, it holds up according to independent NAS lab testing published by sites like NASCompares and ServeTheHome.

The base 2GB DDR4 is the first thing worth upgrading. Synology officially supports up to 6GB in the DS423+ (using a 4GB stick alongside the soldered 2GB), and reviewers consistently note that running Docker containers or Synology’s Virtual Machine Manager benefits significantly from that extra headroom. The 2GB configuration will handle basic file serving and backup jobs, but if the plan involves running multiple packages simultaneously, that upgrade is not optional.

Two M.2 2280 slots support NVMe SSDs for SSD caching, which is a meaningful inclusion. Pairing an NVMe read/write cache with spinning hard drives noticeably improves random I/O performance for frequently accessed files, based on benchmark data from multiple independent NAS review outlets. The reviewed bundle already includes 2x500GB NVMe drives, which covers most caching use cases without additional purchases.

Networking is where the DS423+ shows its age most clearly. Two 1GbE ports with Link Aggregation Support (802.3ad) gives a theoretical maximum of 2Gbps, but real-world aggregated throughput in lab tests tops out around 220 MB/s sequential read under ideal conditions. That is fine for most home and small office scenarios, but it is a bottleneck compared to competing units from QNAP that include 2.5GbE ports at similar or lower price points. If the network infrastructure is already 2.5GbE or 10GbE capable, the DS423+ will be the slowest link in the chain.

Three USB 3.2 Gen 1 ports round out the connectivity, useful for direct-attach backup drives or UPS connectivity. There is no USB-C, which is a minor annoyance but not a dealbreaker at this form factor.

Pros and Cons

Pros:

• DSM 7.x is genuinely the best NAS operating system available. The interface is clean, the package ecosystem is deep (Plex, Active Backup for Business, Hyper Backup, Synology Photos), and updates have a strong track record for reliability and security patches.
• AES-NI hardware encryption support means encrypted volumes do not crater performance the way they would on older or ARM-based NAS units.
• Dual M.2 NVMe slots for caching are included at this price tier, something not all 4-bay competitors offer.
• Fanless thermal design options and a quiet single-fan system makes this acceptable for living spaces or home offices where noise matters.
• The 4-bay SATA configuration supports drives up to the largest available capacities, so total raw storage can scale to 80TB+ with the right drives installed.
• Synology’s 3-year limited warranty and long-term software support cycle reduce total ownership risk.

Cons:

• Dual 1GbE is the biggest technical limitation. Competing 4-bay NAS units from QNAP (TS-464 series) include 2.5GbE ports standard and often come in at lower prices.
• The base 2GB RAM requires an immediate upgrade for anything beyond basic file sharing, adding cost to an already expensive unit.
• The $2,199 price for the pre-loaded bundle is steep. The diskless enclosure alone is available for significantly less, and sourcing drives separately is almost always cheaper.
• No 10GbE option is available without moving to a more expensive Synology tier, unlike some QNAP units that offer 10GbE at the 4-bay level.
• The J4125 CPU, while capable, is a generation behind what some competitors are now shipping with in the same price range.

Who It’s For

The DS423+ makes the most sense for households or small offices already invested in the Synology ecosystem. If there are existing Synology units in the environment, DSM’s centralized management and Synology’s first-party apps like Active Backup, Hyper Backup, and Synology Drive create a genuinely coherent backup and sync architecture that third-party software struggles to match.

It also works well in setups where the primary workloads are file backup, photo library management via Synology Photos, and moderate Plex or media serving to a handful of devices. The J4125 can handle direct-play 4K streams without issue; transcoding is where it begins to struggle, particularly multiple simultaneous 4K transcodes. Families with multiple devices all pulling different format streams should account for that ceiling.

For buyers whose priority is raw speed, 2.5GbE or 10GbE networking, or maximum CPU performance per dollar, the QNAP TS-464 or the slightly higher-tier Synology DS923+ deserve a close look before committing here.

Bottom Line

The DS423+ does not have the fastest CPU, the best networking, or the lowest price in its category. What it has is a mature, well-maintained operating system with one of the deepest package ecosystems in the NAS space, solid build quality, and a feature set that covers the needs of most home power users and small teams. The dual 1GbE limitation is a real constraint worth taking seriously as home networks push toward 2.5GbE switches as a standard.

If the price is acceptable and DSM is a priority over raw throughput, this is a reliable, long-term investment. If the price feels high for the hardware spec, buying the diskless enclosure separately and sourcing drives independently is the smarter path to the same end result.

Check the current price on Amazon