Specifications

The TS-421 uses the same CPU as the older TS-419P II we reviewed in the past. The two NAS servers are nearly identical hardware-wise. The only difference is the 1 GB of RAM the first is equipped with. The Marvel CPU only has one core and is much weaker than even the dual-core Atom CPUs higher-end QNAP NAS servers use, but the Marvel will be enough for home usage, and the TS-421 has enough RAM for its embedded Linux OS.

Up to four HDDs can be installed, but the newer SATA III protocol is not supported. This is of less significance to mechanical drives as SATA III actually only makes sense with fast SSDs, making it worthless in a NAS because it will most likely be equipped with large mechanical drives (HDDs). SATA III in a NAS sounds more like a marketing gimmick. Before purchasing any drives for it, make sure to take a look at the QNAP HDD compatibility list since some HDDs may not work all that well with this NAS.

For networking, the TS-421 is equipped with two Gigabit ports that can be teamed, doubling network transfer speed. However, you need to have a compatible switch with the Link Aggregation Control Protocol (LACP) to exploit port trunking.

The I/O ports of the TS-421 include two USB 3.0 ports. The ports are very useful in a NAS since they make fast transfers to compatible external storage devices possible. Two eSATA ports are also bundled.

The dimensions of the NAS are pretty compact and its net weight is low, so you can easily move it around when needed. Its power consumption is also minimal, allowing for 24/7 operation without any worries about increasing the electrical bill. This is the main advantage of such NAS servers as compared to custom-made PC/NAS systems. The latter consume significantly more. A few more watts may look insignificant, but you have to factor out the difference over the long run, after months or even years of 24/7 operation.

The warranty of the NAS is restricted to only two years, which is unfortunately a common warranty period among NAS manufacturers. The price makes the TS-421 part of the mid-level category.