Four Stream Performance
ASUS supplied two RT-AC88U's so 4x4 thoughput could be tested. This is our second look at Broadcom's 4x4 chipset, so the same tests were run that were performed on NETGEAR's R8500.
For the test, two RT-AC88U's were set up in open air, eight feet apart, one as a normal router and the other in wireless bridge mode. The in-house 5 GHz network was idle and only beaconing (no traffic). Channel was set to 153, bandwidth mode to 80 MHz and everything else set to defaults.
Only one computer was connected via Gigabit Ethernet at each end of the bridge. Baseline tests using Ethernet between the two computers (both equipped with TP-LINK TG-3468 NICs) show the Ethernet link capable of a bit over 940 Mbps in both directions with each direction run separately. So the hardwired part of the link shouldn't be a limiting factor.
Running four simultaneous IxChariot connections downlink, yielded 912 Mbps total downlink throughput. The IxChariot plot below shows shockingly stable and equal throughput for all four connections once things settle down after 15 seconds into the test run. The test was rerun multiple times and I even unscrewed antennas from each router to be sure I was seeing wireless throughput and not Ethernet by accident. What the plot shows is really wireless performance! However, I still didn't see the maximum 2165 Mbps link rate; 1625 Mbps was reported during this test.
Four stream throughput - 5 GHz downlink
5 GHz uplink produced an almost equally good 896 Mbps total throughput, again with very low variation and even distribution among connections.
Four stream throughput - 5 GHz uplink
Since 1024-QAM is supposed to increase the maximum 2.4 GHz link rate to 1000 Mbps, the tests were run again with the 2.4 GHz radio set to Channel 6 and 40 MHz bandwidth mode. The reported link rate was 900 Mbps and the test yielded 580 Mbps of total downlink throughput. Throughput distribution isn't quite as even and it took longer for things to settle down.
Four stream throughput - 2.4 GHz downlink
The 2.4 GHz uplink test produced 541 Mbps.
Four stream throughput - 2.4 GHz uplink
In general, the RT-AC88U did better than NETGEAR's R8500 on these tests.
|Test Description||ASUS RT-AC88U||NETGEAR R8500|
|5 GHz downlink||912||708|
|5 GHz uplink||896||181|
|2.4 GHz downlink||580||433|
|2.4 GHz uplink||541||421|
Table 4: Four stream wireless throughput comparison (Mbps)
ASUS fanbois have been all worked up about the RT-AC88U, judging from SNBForums discussions. But neither our chamber nor real life tests provide reason for such excitement, at least on the basis of wireless performance. What Forum posters seem most excited about is that the router just works. To me, this is sad commentary on how low consumer expecatations for wireless routers have sunk.
I continue to be surprised at the number of people in the SmallNetBuilder Forums who are snapping up this new crop of expensive 4x4 routers based on Broadcom's first attempt at both a 4x4 radio design and the MU-MIMO technology they formerly pooh-poohed (when they didn't yet have a 4x4 solution). Surely, having been bitten by the RT-AC87U's 5 GHz problems caused by its Quantenna radio and by the failure of the promised MU-MIMO functionality to be enabled, buyers would be reluctant to buy another MU-MIMO router without working MU-MIMO. But, at least for ASUS fans, that seems to not be the case.
If you own an RT-AC87U and it hasn't been working out for you and you want to replace it with another ASUS 4x4 router, then, by all means, go for an RT-AC88U. If on the other hand you already have an AC router and it's working fine, there is no good reason to buy this or any other 4x4 router right now. If you just gotta have the latest in Wi-Fi router tech, well, just because, then at least cool your jets a few weeks until CES 2016 to see what new router science experiments await.