More importantly, the WRT1900AC outperformed the RT-AC68U by more than 37 percent when the client was in my home theater, delivering throughput of 382Mbps. The Linksys didn't perform as well at long range (with the client 65 feet from the router in my home office), delivering throughput of 352Mbps compared to the Asus's 430Mbps. On the other hand, if 352Mbps is too slow for you, you should think about stringing some cable.
Comparatively slow at 2.4GHz, but will you care?
For most people, a router's 2.4GHz, 802.11n performance is important only when connecting legacy hardware. In my home, I use that band for the IP cameras in my home-control system and that's about it. So if you're like me, you won't care that the WRT1900AC is a comparatively slow performer on that band. The Asus RT-AC68 was between 8- and 63-percent faster when I measured TCP throughput using the laptop's onboard Intel Centrino Ultimate-N 6300 Wi-Fi adapter, with the smallest delta occurring when the client was furthest from the router.
But there is an explanation for the WRT1900AC's 2.4GHz performance. If you're familiar with wireless networking, you know that routers can bond multiple channels within a given frequency band to deliver one wider channel with extra bandwidth. On the 2.4GHz band, however, there are only three channels that don't overlap. Any router certified by the Wi-Fi Alliance is supposed to disengage from channel bonding if it detects another 2.4GHz router operating nearby, so it won't degrade that network's performance.
The WRT1900AC offers two options on this front: You can configure it to always use a single 20MHz channel, or you can set the router to "auto" mode, in which case it will bond a second 20MHz channel to deliver 40MHz of bandwidth only if it doesn't detect neighboring 2.4GHz networks.
Asus gives you a third option with its RT-AC68U: You can set it to bond two channels by default. The RT-AC68U is also certified by the Wi-Fi Alliance, so it should back down to single-channel mode in the presence of adjacent 2.4GHz networks. My house is located on the middle of a 10-acre parcel of land, but some Wi-Fi adapters I've used pick up exceedingly weak signals from two other networks that are at least 500 feet away. The Asus router ignored them and barreled right along with channel bonding. The Linksys did not, and its performance suffered accordingly.
The WRT1900AC is unparalleled when it comes to transferring files from an attached hard drive: It just screams. You'd likely get the highest performance with an external hard drive that could take advantage of its eSATA port, but USB 3.0 drives are much more common. I used a Western Digital Passport drive with a USB 3.0 interface for my tests.
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