A Closer Look at the RT-AC68U Router

In what has quickly become iconic packaging for ASUS’ wireless networking components, the RT-AC68U comes housed inside a mostly black box. While this package could easily be mistaken for the previous RT-AC66’s the rather tasteful and blatantly different picture of the RT-AC68 will quickly put such mistaken identity issues to rest.The accessories which accompany the RT-AC68U are also very similar to that of the previous AC66 router. They consist of a well done installation booklet, an external power adapter, installation CD and three large external antennas. ASUS have not included the previous generation’s vertical mounting plastic bracket as this has been integrated directly into the RT-AC68’s chassis.As you can see, the new RT-AC68U uses an entirely redesigned chassis. With just a cursory glance no one will mistake the AC68 for the older AC66U or ‘Dark Knight’ N66U but it does pay homage to these classic designs and both obviously contributed heavily to its overall. Like the previous AC66, the AC68 has a wedge shaped appearance, has a relatively compact footprint of 220 x 83.3 x 160mm and is fairly lightweight at 640grams. It also uses adjustable and detachable RP-SMA antennas and aftermarket high gain antennas are compatible with it as well.Also like the AC68U also uses a faux carbon fiber front, has the status LEDs located in the bottom left corner of the front and even has the ASUS logo and model number on the top right of the front panel just like the RT-AC66U. This is where the similarities between these two designs end. Unlike the AC66U which was router capable of either horizontal or vertical mounting the AC68U is a vertical-only router. This decision does have both negative and positive impact on the AC68U but in our opinion, it is for the better. Personal experience with the AC66U did make it readily apparent that horizontal orientations could lead to overheating.By integrating the stand directly into the base of the AC68U the end result is not only a more stable design when in vertical orientation but also one that is less likely to slide around as ASUS has also included rubber strips running along the bottom of the AC68’s base.ASUS have moved the various I/O ports to the bottom while leaving the three dual band external antenna ports at the top. By separating the wired from the wireless connections, the RT-AC68U should have improved wireless reception abilities especially for consumers using lower grade RJ45 cabling where some interference could occur. It also makes for a much tidier appearance when all the RJ45 ports are in use as they are nicely hidden behind the router.The I/O panel configuration and layout has also been modified when compared to the AC66U. First and foremost the WiFi on/off and WPS buttons have been relocated to the side of the AC68U. The right side is dedicated to the four RJ45 Gigabit ports and the left has the blue WAN port as well as the power button, power port and the dual USB ports. One of the two USB ports has been upgraded from USB 2.0 to USB 3.0.Above this cluster of ports on the right side is a small recessed reset button which allows consumers to do a soft-reset of the router. Holding it down for more than five seconds will act the same as a hard reset. In between the left and right port cluster is a lone button which controls the LEDs of the unit. Unfortunately, by pushing this single button you not only turn of the rather bright and annoying rear LED (which illuminates the ASUS logo) but also the front status LEDs as well.By removing the plastic external chassis, a quick glance shows a somewhat similar internal architecture to that of the RT-AC66U, but with some noticeable improvements as well. Both rely on 256MB of RAM, have 128MB of NAND storage, and include a Broadcom BCM4360 controller to take care of 5GHz 802.11AC networking duties. Both also use large heatsinks to keep the various parts cool and both are missing the internal microSD slot of the RT-N66U.Like the exterior, there are some major differences between the AC66U and AC68U here as well. First and foremost the single heatsink design has been replaced with a dual chamber design, with one large heatsink on the front of the PCB and a smaller one on the back. Instead of two 128MB DD2 RAM ICs, there is a single DDR3 256MB IC for increased memory bandwidth and performance.One of the other noteworthy improvements is the replacement of the older Broadcom BCM4331 controller with a second BCM4360. Amongst its list of improvements over the BCM4331, the BCM4360 adds 256-QAM modulation and encoding abilities to 802.11N networks.When you combine three spatial steams with 256-QAM encoding on 80Mhz channels you get 1300Mbit/sec abilities, but since 40Mhz is the most 802.11N is rated for this results in 600MBits/s connectivity. The only caveat is that both ends of the wireless network have to support 256-QAM which drastically limits the usability of this feature at this time. However, the PCE-AC68 does support 256QAM on 802.11N connections and similar 600Mbit/s adapters are slowly trickling on to the market.ASUS even boosted the main processor abilities of their latest router and instead of the older 600Mhz dual core Broadcom BCM4706 System On a Chip found inside the RT-AC66U, the newer Broadcom BCM4708 SoC is being used. This dual core A9 Cortex processor runs at 800MHz and should have the computational ability to handle more demanding environments than the 4706.It is puzzling why ASUS went with the 4708 instead of the higher performance -1GHz- 4709 as that would have even further increased theoretical performance. This does put the RT-AC68U at a distinct disadvantage when compared newer routers like the NETGEAR ‘NighHawk’ R7000 AC1900. However, hardware is only part of this equation.