If you're after a compact four-bay desktop NAS with modern networking for work and media backups, the TerraMaster F4-425 Pro NAS system has dropped to $680 (was $800) at Amazon
We've tested this exact configuration, and found it's a genuine upgrade over its predecessor with dual 5GbE and a third M.2 slot. But it's not for everyone.
Why we recommend it
In our review, we awarded this NAS device 4 stars, praising the move to dual 5GbE over the previous generation's 2.5GbE as a real, tangible upgrade for large file transfers and multi-user environments. The third M.2 slot gives more flexibility for caching than most four-bay NAS units in this price range offer. The new N350 processor also runs cooler and more efficiently than its predecessor, which matters for a device meant to run 24/7.
TOS 7 is the most polished version of TerraMaster's operating system yet, with solid Docker and VM support, a comprehensive backup suite, and the TRAID hybrid array mode that lets you mix drive sizes more efficiently than standard RAID.
Our review was direct about where it falls short compared to competitors, calling it a NAS hamstrung by PCIe lanes, since both the M.2 slots and networking share a limited nine-lane PCIe budget. If you don't need to push past those limits, it's still a capable, efficient NAS for the price.
Price Context & Historical Value
This deal cuts the 16GB configuration's $799.99 list price by $120, about 15 percent off. That's a modest but genuine discount rather than an inflated anchor price, and it narrows the gap with TerraMaster's own store, which has periodically discounted this same configuration to around $640 to $670 during promotions.
Should you buy it?
✅ Buy the TerraMaster F4-425 Pro if... you want a flexible four-bay NAS with modern 5GbE networking and don't need 10GbE speeds, you value low power consumption and quiet, cool running over raw compute power, or you like the idea of experimenting with AI-assisted NAS administration.
❌ Skip the TerraMaster F4-425 Pro if... you want a 10GbE port or Thunderbolt/USB4 connectivity, you plan to fill all three M.2 slots with fast NVMe drives for local storage, or you want to run demanding local AI workloads on the NAS itself.
The Catch: What to know before you buy
The three M.2 slots are limited to PCIe Gen 3 x1 bandwidth, capping NVMe performance at roughly 1GB/s regardless of the drives you install, so there's little benefit to using expensive high-end SSDs here. There's no 10GbE port, not even as an upgrade option, and no Thunderbolt or USB4 for fast external expansion. The single RAM slot also means upgrading beyond the included 16GB requires removing it entirely rather than adding a second module. On top of that, the drive trays still lack physical locks or number labels - a longstanding TerraMaster quirk our reviewer has flagged across multiple generations.
