USB and Power Performance
To test the USB performance we hooked up a 120GB Corsair Neutron GTX SSD inside a USB 3.0 enclosure. Using a Gigabit-connected desktop we then mapped the USB network storage as a drive within Windows and ran a simple CrystalDiskMark sequential benchmark test.
Both other routers make use of USB 2.0 ports so the DSL-AC68U leads the way with its USB 3.0 port. The maximum theoretical performance from our testing scenario would be 1Gbps (125MB/s); we recorded just under half that. Relatively-speaking, this is still high performance for router-attached USB storage and the 55MB/s download speed means you could easily have multiple users accessing high bit-rate video streams at the same time without any issues.
Power consumption
We observed power consumption under three different scenarios. The first, 'low usage,' entails having the router on and connected to the Internet with WiFi broadcasting, but no USB storage is attached and network traffic is minimal. The second, 'network load,' involves having two connected devices, one for each band, stressing the WiFi and Gigabit with large file transfers to a Gigabit-desktop client. The final scenario, 'USB & network load,' combines the previous scenario with a Gigabit-connected desktop client accessing the USB connected storage.
The DSL-AC68U, as you might expect, uses the most power. The reason is the highest-spec hardware; an onboard dual-core CPU, USB 3.0 support and higher-strength 5GHz antennae. All things considered its rather paltry sub-20 watt power consumption is unlikely to make a significant dent in your electric bill, even when operated 24/7.
