SmallNetBuilder

Wireless Performance - 2.4 GHz 2 Stream

I used our standard test method to test the the AC66's two-stream N wireless performance using our standard two-stream client, an Intel Centrino Advanced-N 6200 in a Acer Aspire 1810T notebook running Win 7 Home Premium SP1 (64 bit). 2.4 GHz tests were run on Channel 1 and 5 GHz band tests on Channel 36. As noted earlier, data was taken with 3.0.0.4.164 firmware.

For performance comparison, I chose the other two draft 11ac routers tested so far, the Buffalo WZR-D1800H and NETGEAR R6300 and threw in the ASUS RT-N66U for those of you wavering between the AC and it.

The comparison tables are large, so I'm going to provide links that will open them in a new window/tab to make things easier. Let's start with the Performance Table for Two-stream 2.4 GHz.

Like the N66, the A66's performance with two-stream clients is in the same ballpark as the other Broadcom-based draft 11ac routers. The AC66's main strength is Location D throughput, which tends to indicate superior range. This is reinforced by the 30 Mbps Location F downlink result in 20 MHz mode. But other Location F results aren't as good.

The IxChariot plot summary below for 20 MHz mode downlink shows fairly large variation in Locations A, C and D and a lot more in Location F.

ASUS RT-AC66U IxChariot plot summary - 2.4 GHz, 20 MHz mode, downlink, 2 stream

Throughput is a bit more stable, although with frequent downward spikes on many of the other plots linked below:

• 2.4 GHz / 20 MHz uplink
• 2.4 GHz / 20 MHz up and downlink
• 2.4 GHz / 40 MHz downlink
• 2.4 GHz / 40 MHz uplink
• 2.4 GHz / 40 MHz up and downlink

Wireless Performance - 2.4 GHz 3 Stream

Next, we'll look at the Performance Table for three-stream 2.4 GHz.

Although the AC66 and N66 use the same Broadcom SoC, performance is a bit different, perhaps due to the different external components used. But the performance table still shows many similarities between the two. Location D and F throughput is again pretty good, especially in 40 MHz downlink. But 40 MHz mode uplink results are, as mentioned earlier, higher than I've ever seen for strong signal test locations A and C.

The IxChariot plot summary below for 20 MHz mode downlink once again shows sizeable periodic downward throughput spikes.

ASUS RT-AC66U IxChariot plot summary - 2.4 GHz, 20 MHz mode, downlink, 3 stream

You will see similar effects on these other plots:

• 2.4 GHz / 20 MHz uplink
• 2.4 GHz / 20 MHz up and downlink
• 2.4 GHz / 40 MHz downlink
• 2.4 GHz / 40 MHz uplink
• 2.4 GHz / 40 MHz up and downlink

Wireless Performance - 5 GHz 2 Stream

Next, we'll look at the Performance Table for two-stream 5 GHz.

The AC66 isn't that impressive in this group of tests. I suspect, however, that there could be overload issues causing the unusually low result in Location A downlink, 20 MHz mode. The takeaway for this group of tests is that all products are about equal.

The IxChariot plot summary below for 20 MHz mode downlink shows some rate-shifting behavior in the location A run. As is my custom, I reran the test a few times and got similar results.

ASUS RT-AC66U IxChariot plot summary - 5 GHz, 20 MHz mode, downlink, 2 stream

Throughput stability is generally good in the other plots linked below:

• 5 GHz / 20 MHz uplink
• 5 GHz / 20 MHz up and downlink
• 5 GHz / 40 MHz downlink
• 5 GHz / 40 MHz uplink
• 5 GHz / 40 MHz up and downlink

Wireless Performance - 5 GHz 3 Stream

Finally, we'll look at the Performance Table for three-stream 5 GHz.

This group of results shows the N66 winning more comparisons than the AC66. The AC66's speeds in this mode are not knock-your-socks-off good, with only two Location A results coming within spittin' distance of 100 Mbps.

The IxChariot plot summary below for 20 MHz mode downlink shows some pretty long and big dropouts.

ASUS RT-AC66U IxChariot plot summary - 5 GHz, 20 MHz mode, downlink, 3 stream

The other plots linked below show more of the same and some rate-shifting at the start of 40 MHz mode uplink tests:

• 5 GHz / 20 MHz uplink
• 5 GHz / 20 MHz up and downlink
• 5 GHz / 40 MHz downlink
• 5 GHz / 40 MHz uplink
• 5 GHz / 40 MHz up and downlink

Closing Thoughts

Buyers in search of a high performance wireless router should stick with the RT-N66U Dark Knight vs. the RT-AC66U, at least for now. Given the reports in the SNB Forums, it looks like the AC66's firmware is not yet stable, with some features disappearing to be worked on and others partially functioning. So if you are expecting smooth sailing with the AC66U, you may be unpleasantly surprised.

Even if you're willing to pay for the privilege of helping ASUS debug its product, you are unlikely to be rewarded with higher performance. For most uses, i.e. with two-stream clients, you'll get essentially the same performance in the 2.4 GHz band and, at least with the firmware used, better results in 5 GHz with the Dark Knight.

If you are one of the few folks with three-stream N devices, I wouldn't let the high 40MHz mode 2.4 GHz uplink results influence your choice. First, you shouldn't be using 40 MHz mode in the overcrowded 2.4 GHz band anyway and second, I think the abnormally high 40 MHz mode uplink results are a fluke.

As I've said before, there is no reason to jump on the draft 11ac bandwagon at this point in hope of improving speed or range for two or three-stream N devices, because 11ac brings nothing to the table for them. 11ac should (at least that's the plan) improve throughput for single-stream N devices. But new chipsets supporting draft 11ac need to be baked into smart phones, tablets and other mobile thingies before that dream becomes reality.

If you're looking to "future proof" your wireless router choice, the current crop of draft 11ac routers isn't a good choice given their first-generation draft 11ac chipset. Router-side devices will probably benefit from a move to second (or third) generation 11ac chipsets, which hopefully will be designed to the final standard and include multi-user MIMO support.

The only viable argument for buying the RT-AC66U, or any other draft 11ac router, is to buy two and use one as a bridge to form a high-bandwidth 5 GHz link to a HD media player. But even there, I think using a three-stream N router and less-expensive bridge like the ASUS EA-N66 or TRENDnet TEW-640MB will get you to the same place and let you save your money for the inevitable move to an 11ac router, once the standard is released and the dust settles.