I’ve been trying to find solid, reliable information on a direct comparison between these two devices. After little luck (and mostly conjecture, theory, and the odd but non-detailed anecdote on forums) I’ve decided the best way to find out is to simply have both devices.
The differences are minimal between the two units. Upon unpacking the AC66U, everything in the box looks identical to the N66U (even the way it is packed). The only differences I could spot were a different type of ethernet cable included (one of those flat, thin ones, I’m not sure I’d trust it to do GigE stuff), and the little power button on the AC66U was already pushed in (On), likely to try and be less confusing to inept consumers who might have wondered why their N66U doesn’t turn on after plugging it in.
Setting up the AC66U is once again very similar to the N66U; logging into the web admin panel for the first time asks the same questions, with the exception of a new “mode” for the AC66U, the Media Bridge (pictured below). As it states, you need two AC66U units to use this mode, which I don’t have or need, so I will skip this and set it up like normal. For the work that I do though, this may provide an interesting option for some clients moving forward.
The unit shipped with firmware rev 184.108.40.206.260, which I immediately updated to Merlin’s 4.270.26b. Props to RMerlin for adding the nice little features to his firmware, as well as having it completely stable for some time now. As usual, only do firmware updates over hardwire connections. One thing I did notice is that the AC66U seemed to update it’s firmware faster – the N66U typically takes about 4 minutes from upload > full reboot, the AC66U took only 2 minutes, despite the warning saying give it “about 3 minutes”, and it asked me to reboot the router manually via the little power button instead of auto-rebooting. In practice it takes the same amount of time, but the N66U is fully automated.
An extremely nice feature of Merlin’s firmware beyond rev 270.26b is that you do not have to restart the entire network when you want to add static IP allocation to the DHCP server on the LAN page. Quite a time saver for my work!
On to performance comparisons.
First thing I noticed was that my N66U was reporting temperatures of 51c and 53c for the 2.4g and 5g radios respectively, while the AC66U was reporting 50c and 56c. So more or less the same temperature output from the brotherly units, with the AC66U being very slightly warmer. You might not want to use either of these units in a cramped attic in Texas in the summer, but I think that stands true for most tech.
On to signal strength, which is being measured by my Galaxy Nexus (which like most other smartphones does not support 802.11AC, and doesn’t have the best N chip in it). I purposefully chose to measure the strength on my phone because I figure if the phone can see and connect to it, everything else will be able to without issues.
For reference, my router(s) are in the basement and my office is located directly above where my network equipment is, so the signal is only traveling about 5 ft through a wooden floor. They are both using the same firmware version and the same settings, with the only difference being channel selection.
Office / Bedroom / Backyard test locations:
The conclusion I drew from these signal tests is that these units currently put out pretty much the same signal strength with minor variations (+/- 5 dBm) and that these minor variations should not significantly impact usage. Often I found that if one had a stronger 2.4g signal, the 5g signal was weaker. Also, I could probably move my network equipment to somewhere not in the basement for better outdoor coverage, although I don’t really care about that!
Now, for the LAN (wired) speed throughput tests:
In case the pictures are too blurry from compression, the results are very similar, averaged over 10 tests. The N66U had an average LAN read performance of 882 Mbps (which is in line with what smallnetbuilder found) and the AC66U had an average read performance of 919 Mbps.
To summarize this, the N66U has an MSRP of around $170 CAD, while the AC66U retails for around $200 CAD. Given the similar performance output of these two routers, it’s difficult to recommend one over the other definitively. For the extra $30, you currently gain only one thing, the AC66U’s “Media Bridge” mode.
However, moving forward into the near future, 802.11AC will become more widely adopted – Samsung’s Galaxy S4 and the HTC One (due in April/May 2013) have both been confirmed to be the first smartphones to ship with an 802.11AC wifi chip embedded, and it is rumored/expected for Apple to follow suit with their iPhone 5s and their 2013 lineup of Mac computers. And yes, while it’s true that for Joe Average that 802.11AC offers no tangible benefits over 802.11N at the present time, tech gurus, media junkies, and multi-user-multi-device homes might appreciate the “future-proofing” that the RT-AC66U offers for $30 more.
Both routers are excellent, high end products, and both are still undergoing active development and refinement via firmware updates, both officially from Asus and from third parties such as RMerlin, Shibby Tomato and DD-WRT. I have been using the N66U as my daily home router for about 4 months now and it never gave me a single problem; I will be using the AC66U as my daily home router now and I hope (expect) to see the same reliability, speed and performance.