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ASUS RT-N66U Dark Knight Dual-Band Wireless-N900 Gigabit Router Reviewed

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Dark Knight Dual-Band Wireless-N900 Gigabit Router
At a glance
ProductASUS RT-N66U Dark Knight Dual-Band Wireless-N900 Gigabit Router   [Website]
SummaryBroadcom-based simultaneous dual-band, Gigabit, three-stream 802.11abgn router with USB printer and multi-featured drive sharing and PPTP VPN server
Pros• Outstanding wireless performance
• Many features including WWAN backup and VPN server
• Redesigned GUI
• 2 USB ports
Cons• Work in progress for some features (DLNA, VPN)
• Incomplete and incorrect documentation

Typical Price: $119  Check NewEgg  Check Amazon


Updated 2/20/2013: Corrected RT-N56U information
Updated 2/9/2012: Added Wireless Performance and Conclusion
Updated 2/8/2012: Deleted RT-N56U alternate firmware availability

The SNB Forum thread about the RT-N66U has been one of our most active with 478 posts and 80,000+ views as I write this. And our review of the "Dark Knight"'s predecessor, the RT-N56U "Black Diamond" continues to be our most read review each week—almost a year now after it posted.

This is an awful lot of excitement for a single-band an N600 Gigabit router with a few USB ports. But there are enough people who think buying much more routing throughput than they could ever even hope to use gets them a better router, no matter how many times I tell them it doesn't.

Those folks who got worked up over the "Black Diamond" will find even more to go ga-ga about with the Dark Knight. First, it's Broadcom-based, which opens up the possibility of alternate firmware support, unlike the Ralink-based RT-N56U. While DD-WRT isn't yet available, TomatoUSB (shibby) appears to be. But I'm getting a bit ahead of myself. Let's start with the basics.

The RT-N66U is a simultaneous dual-band three-stream "N-900" router with one Gigabit WAN port, four switched Gigabit LAN ports and two USB 2.0 ports that support drive and printer sharing. "N-900" means that it will support 450 Mbps link rates when both radios are set to 20/40 or 40 MHz channel bandwidth.

The first thing that struck me about the 66U was the size of the box it came in, which is almost 16" wide. The router itself is only about 8" wide, which is about the width of its primary competition, Cisco's Linksys E4200V2 and NETGEAR's WNDR4500. So the main reason for the bigger box could be to impress naive buyers (Gee, Martha, if the box is bigger then it must be a better router!).

Figure 1 calls out the lights, ports and switches on the front and rear panels where you can see that ASUS is making a few moves counter to current home router design trends. They have included a full complement of stylish blue front panel link/activity indicators. But more notably, they are using external, upgradeable antennas.

RT-N66U front and rear panels
Figure 1: RT-N66U front and rear panels

This will excite those who like the idea of being able to install higher-gain antennas. But in reality, it's difficult to find higher-gain dual-band antennas. There is also the potential of reduced performance from using dual-band vs. separate single-band antennas. And there is always WAF to consider.


ASUS decided to emulate Cisco and asked the FCC to delay the release of the internal photos it filed, so I was going to open up my sample after I finished testing. But a little searching turned up some very nice photos in's review, which I'm using instead.

The Dark Night that is shipping is actually the second revision (B1) of the design. VR-Zone got an early peek at the product last October in its A1 form, which had a fan as shown in Figure 2. Note that the A1 never shipped and didn't even make it to the FCC. The B1 is the first shipping model.

RT-N66U A1 board w/ fan
Figure 2: RT-N66U A1 board w/ fan
[photo credit: VR-Zone]

Figure 3 shows the board from the current B1 design, with a hefty heatsink replacing the fan (this is the reason why the router is so heavy). This is a smart move by ASUS, since fans fail and are noisy, neither of which would enhance the 66U's appeal.

RT-N66U B1board w/ heatsink
Figure 3: RT-N66U B1 board w/ heatsink
[Photo credit:]

Figure 4 shows the heatsink removed, which doesn't reveal much due to the RF "cans" covering all the good stuff. Note the SD card slot at the lower right, which has some folks excited over in the Forums. But so far, it doesn't do anything and it's not externally accessible anyway.

RT-N66U B1board w/o heatsink
Figure 4: RT-N66U B1 board w/o heatsink
[Photo credit:]

The bottom view in Figure 5 is pretty clean, containing only a lone 32 MB flash device.

RT-N66U B1 board bottom
Figure 5: RT-N66U B1 board bottom
[Photo credit:]

Reviewer documents that ASUS sent detailed the key components used. It turns out that the Dark Knight's design is very similar to another dark-colored router, NETGEAR's WNDR4500. Table 1 shows that the designs are very similar for the CPU and radios. Both use a 600 MHz Broadcom BCM4706 processor and a BCM4331 single-chip 3x3 SoC for each radio.

  RT-N66U WNDR4500
CPU Broadcom BCM4706 Broadcom BCM4706
Switch Broadcom BCM53115 (?) Broadcom BCM53115 (?)
RAM 256 MB 128 MB
Flash 32 MB 128 MB
2.4 GHz Radio - BCM4331 - BCM4331
- 2.4 GHz power amps (x3) (?)
5 GHz radio

- Broadcom BCM4331

- Broadcom BCM4331
- 5 GHz power amps (x3) (?)

Table 1: ASUS RT-N66U and NETGEAR WNDR4000 component comparison

The 66U's webpage refers to "built-in Wi-Fi amplifiers", but doesn't provide further details. I'm guessing transmit only and on both bands. I also have to guess on the switch, so a Broadcom BCM53115 is what I'm thinkin'.

Given the similarity of silicon, it will be interesting to see how the 66U's three dual-band antenna approach matches up to the WNDR4500's six dedicated-frequency antennas when it comes to wireless performance.

Related Items:

WD My Net N900 5 GHz Retest
ASUS RT-N66U and Linksys EA4500 / EA4200v2 Wireless Retest
Draft 802.11ac Goes The Distance. Buffalo WZR-D1800H AirStation Review
Slideshow: Netgear WNDR3300 RangeMax Dual-Band Wireless N Router
Slideshow: D-Link DIR-628 RangeBooster N Dual Band Router

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Average user rating from: 15 user(s)

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Tomato bridge

Overall rating: 
Reviewed by Jason
May 15, 2014
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Was surprised it didn't have a bridge feature out of the box, but we planned on loading tomato anyways. Using it to bridge 60mb internet through two floors and it is working perfectly, nice steady connection.


Dead in less than 3 months! Deceitful customer service!!

Overall rating: 
Reviewed by TomD
April 12, 2014
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Works fine for a little over 2 months. Woke one morning, no wifi on any device... AC adapter died. 1st ASUS tech: AC adapter is external accessory and not included in warranty. Go buy another AC adapter. 2nd ASUS tech: It's faster to go buy another AC adapter. Lots of blah blah blah showing a company that is full of deceits doing their best to not honor their warranty. Don't believe me? Try calling and tell them you have a dead AC adapter. Here's their number: 812-282-2787


Best choice in dual band 450 Mbps routers, and a few tips for optimum results

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Reviewed by Robbster
July 09, 2013
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Researched VERY carefully before choosing the Dark Knight as the foundation for home network upgrade. The primary goals for the upgrade were increased device to device speed and to enable a more robust file sharing and backup scheme. The Dark Knight reviewed the best, and has delivered on all these counts so far in my setup. BUT, you do have to master some aspects of the the configuration to get the most out of it. Specifically rejected the ASUS RT-AC66U and the draft 802.11AC devices generally as too immature. While I like *leading* edge and the promise of 802.11AC speeds (which will be fabulous when they are actually delivered reliably), it seemed that AC is on the *bleeding* edge right now based on device reviews and the status of the draft AC spec. So, Dark Knight it is!

Here is what I learned so far. Note that this is what works for me in my specific suburban home and neighborhood setting, and other environments will of course affect router function...

Who is this for?
*Tech savvy who want maximum performance at reasonable cost and with a pretty straight forward configuration process. I conclude this because, at the end of the day, I believe you have to dig into the configuration a bit to really get what you want from this router, BUT, fortunately, the Dashboard UI is pretty straight forward given the degree of flexibility built into this device.
*The less sophisticated user who still wants top performance. They can use the Quick Internet Setup to be up and running about as painlessly as is possible these days, and the defaults plus the raw capability of the device will give good performance. But they may not realize full benefits if they don't poke into the config, and at least run firmware updates.

Paired Adapter
TRENDnet 450 Mbps Dual Band Wireless N USB Adapter TEW-684UB (Black)
*Of course you have to pair the N66U with a similarly spec'd adapter, and the TRENDnet 684UB works great! Am getting full 450Mbps links speeds on 5GHz band, and 2.4GHz speeds in the 144-300 Mbps range despite the crowding in this band.

Router Configuration
*Update Firmware. Obviously for this router, regularly updating the firmware is important, and Asus makes this super easy right from the top of the main device screen (i.e., the Dashboard). I think it's really cool how Asus is working the firmware constantly with a community of users, and also supports open source firmware as well. Asus is easily the most responsive and proactive firmware developer I've ever seen in 20 years of working with wireless networks and routers. To me, this is a competitive advantage vs. the "few updates then done" approach of other vendors who leave us stuck with firmware issues as they move on to the next device.

*Crank the power. Once I made my way to the >Advanced Settings/Wireless/Professional/Tx Power Adjustment< setting and maxed it out (200mW), link speeds and connection stability went WAY up in my home. 5GHz connections benefited the most, going right up to link speeds of 450 Mbps a 3 rooms away, and 2.4GHz link speeds increased 50%.

*Allow 40MHz band width on 5GHz. The total bandwidth of 5GHz wifi is much greater than 2.4GHz, AND it's less crowded so far, so setting the router to use the higher capacity of a 40MHz connection maximizes speed on this band. >Advanced Settings/Wireless/General/Channel Bandwidth/20/40< I find that my router + adapter combination regularly bumps the 5GHz connection up to 40MHz channel bandwidth with the resultant link speed of 450Mbps.

Connected Dual Drive RAID1 USB Hard Drive = Cheap NAS
Vantec Dual 3.5-Inch SATA to USB 3.0 and eSATA with JBOD/RAID 0/1 External Hard Drive Enclosure (NST-400MX-S3R)
WD Red 3 TB NAS Hard Drive: 3.5 Inch, SATA III, 64 MB Cache - WD30EFRX
Popped two Western Digital RED 3TB drives (optimized for 24/7 NAS use) into the Vantec 400MX dual slot RAID enclosure, configured for RAID1, formatted the resultant RAID drive through direct connection to PC, then attached this to the USB port on the Dark Knight, and it was immediately recognized. Kudos to ASUS for firmware that now supports connected hard drives larger than 2TB! Accessed the new shared drive through \ as an address in a Windows Explorer window (not browser, the FILE explorer). Then added the USB drive as a Favorite in Explorer. Simple, fast access to shared file storage. Getting just 5MBps (40 Mbps) transfer rates to the attached RAID volume. Slowish, but useable. Tried streaming some AVCHD 1080p content from the drive and it worked perfectly, no stutters at all, so HD streaming from attached storage looks pretty good.

Summarizing Pros and Cons to date

+ Outstanding speed when combined with similarly spec'd adapter
+ Ability to bump up Transmit power makes for much better link speeds across typical house size.
+ Very powerful and flexible set of features/options, with an easy way to configure them through the Dashboard UI.
+ Easy storage attachment and access
+ Can stream HD from attached storage
+ Frequent Firmware updates with lots of user input to the process
+ Supports attached storage greater than 3TB, with GUID vs. MBR partitions.
+ Active user community online

- Slowish write speeds through network to attached storage. Wish for this to be de-bottlenecked somehow, either in firmware, QoS settings, or through faster connection from router to storage device.

Features I like but have not explored

* VPN, FTP, secure Internet access
* Apps for router
* Multimedia server/sharing
* UPnP integration, e.g., with DirectTV or AV Receiver

Will update as I learn more...

Highly recommended!

*******1/11/2012 update successful UPnP/DNLA access **********

Successfully connected to the attached drive on the router from both my AV Receiver Onkyo HT-S8409 7.1-Channel Network A/V Receiver/Speaker Package, and BluRay DVD player Panasonic DMP-BDT220 Integrated Wi-Fi 3D Blu-ray DVD Player. Accessed both videos and photos stored on the attached drive and displayed them on connected HD TV. So, the DNLA/UPnP features of the Black Knight router worked successfully with DNLA-enabled AV devices on my home network. Very handy!


Very Satisfied with this Router

Overall rating: 
Reviewed by Unknown
June 20, 2013
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This is one of the best consumer router ever . There are no connection drop outs and excellent design to blend into any home .



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Reviewed by Steven Chorkley
April 21, 2013
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I have thousands of connections at one moment and the internet is always in use, either by my HomeServer downloading films or TV Shows or daily usage. Never had to reboot this router once! WiFi Coverage beats any router I have had including the RT-N56U!!!!!!!!

The router is capable of any tasks you need and the GRE port forwarding is welcomed!

I don't care how good you think your current router is, this router is still the best on the market!

I must mention though this is the first router I have spent more than £60, and I am now happy with my Home Network. Power line, WiFi and 10m of Cat Networking. (I don't dare rip the walls out of a 1700's listed building!!!!! And the house is to big for the WiFi signal to reach the hole building so Power Line must be used, although not as effective as it should be due to old wiring,

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