ASUS RT-AC66U – Speed Test

ASUS RT-AC66U is going for some speed test!

The ASUS RT-AC66U is the latest offering from ASUS featuring the 802.11ac wireless standard. The 5th generation 802.11ac chipset delivers concurrent dual-band 2.4GHz/5GHz for up to a blazing fast speed of 1.75Gbps (450Mbps on the 2.4GHz and 1300Mbps on the 5GHz). The speed on the 5GHz channel is almost 3 times faster than 802.11n (up to 450Mbps)!

So how does it really perform wirelessly? Lets find out.

The equipments involved are:

  • ASUS RT-AC66U on firmware
  • HP EliteBook 2560p with Intel Centrino Advanced-N 6205 (2×2) – Up to 300 mbps data rate
  • iMac 27″ on wired LAN


The speed test (methodology)

So how will the test be conducted this time round? I been searching for a open-source software that is similar to the ixchariot and I have found one that runs on Mac, Linux and Windows – Iperf. Iperf is a network testing tool that can create TCP and UDP data streams and measure the throughput of a network that is carrying them.

A series of upstream (write) and downstream (read) tests will be conducted for wireless on 2.4 GHz (40 MHz), 5 GHz (40 MHz) and 5 GHz (80 MHz). 3 concurrent data streams will be used to saturate the wireless link over 60 seconds. Speed samplings are captured every 10 seconds.


Wired Benchmark (LAN-LAN)

Before I test the wireless performance, I always do a baseline test to ensure that none of the equipments or software is the bottleneck. The result of the wired benchmark is as follow:

The LAN-to-LAN speed is within expectation, achieving a average read and write speed of 931 Mbps (Megabits per second).

Direction Min (Mbps) Avg (Mbps) Max (Mbps)
Upstream 928 931 933
Downstream 928 931 933


Wireless-N 2.4GHz (40MHz)

This speed test is conducted on wireless-N 2.4 GHz using 40 Mhz channel width. I could not get a reliable read and write test result due to the congestion on the 2.4 GHz spectrum. In the noisy environment, the ASUS RT-AC66U achieved an average 66.5 Mbps write speed and 64.5 Mbps (Megabits per second) read speed.

Direction Min (Mbps) Avg (Mbps) Max (Mbps)
Upstream 59.6 66.5 72.6
Downstream 60.8 64.6 70.3


Wireless-N 5.0GHz (40MHz)

The wireless-N 5 GHz 40 MHz channel width is less congested in my area so the following results are a lot better than the 2.4 GHz ones. The ASUS RT-AC66U achieved an average 155.5 Mbps write speed  and 139.1 Mbps (Megabits per second) read speed.

Direction Min (Mbps) Avg (Mbps) Max (Mbps)
Upstream 152 155.5 158
Downstream 136 139.1 147


Wireless-N 5.0GHz (80MHz)

This test was conducted using another ASUS RT-AC66U as a wireless client. The ASUS RT-AC66U supports Media Bridge mode which allows one to create a high throughput 802.11ac wireless link between two RT-AC66U.

The primary RT-AC66U’s 5 GHz band was fixed on 80 MHz channel width for this test.

The ASUS RT-AC66U achieved an average 225.7 Mbps write speed and 175.8 Mbps (Megabits per second) read speed. Impressive!

Direction Min (Mbps) Avg (Mbps) Max (Mbps)
Upstream 216 225.7 232
Downstream 160 175.8 181



The wireless performance on the 40 Mhz channel width (for both 2.4 GHz and 5 GHz) of both the ASUS RT-AC66U and ASUS-N66U does not differ much.

In my opinion, both the ASUS RT-AC66U and ASUS RT-N66U are similar in wireless performance on the 802.11b/g/n standards.

However, I am impressed by the 802.11ac performance as it is at least 1.5 times better than the existing 802.11n performance! I have done a (quick) wireless throughput test on 802.11ac with 5 data streams and the results simply scales up (362 Mbps write and 289 Mbps read).

Direction Min (Mbps) Avg (Mbps) Max (Mbps)
LAN Up 928 931 933
LAN Down 928 931 933
2.4GHz (40MHz) Up 59.6 66.5 72.6
2.4GHz (40MHz) Down 60.8 64.6 70.3
5.0GHz (40MHz) Up 152 155.5 158
5.0GHz (40MHz) Down 136 139.1 147
5.0GHz (80MHz) Up 216 225.7 232
5.0GHz (80MHz) Down 160 175.8 181


The ASUS RT-AC66U‘s wireless Media Bridge feature is really useful if you need to link up 2 locations wirelessly. For example, a wireless link to your TV console which houses your media player and gaming consoles. Or perhaps you want to link up your 2 storey house such that a dedicated RT-AC66U serves each floor.

So if you are going down to the nearest store and don’t know what to pick up, my advice will be getting the ASUS RT-N66U if you are  tight on budget. However, if you need to link up your multimedia set up at home, then getting the ASUS RT-AC66U will be a wiser choice as you will definitely see a speed boost on the wireless 802.11ac.


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The different parts of this review series:

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