Four Stream Performance
NETGEAR supplied two R7800s so maximum 4x4 thoughput could be tested. Two R7800s were set up in open air, six feet apart, one as a normal router and the other in wireless bridge mode (found in Advanced Setup > Wireless Bridge). The in-house 5 GHz network was idle and only beaconing (no traffic). Channel was set to 153, bandwidth mode was in its default 80 MHz mode and everything else was set to defaults, including MU-MIMO enabled. Given the 4x4-to-4x4 nature of the link, MU-MIMO doesn't come into play.
I connected only one computer via Gigabit Ethernet at each end of the bridge. Baseline tests using Ethernet between the two computers 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. The bridge R7800 reported a best case link rate of 1560 Mbps during this test.
The simultaneous up and downlink test yielded 981 Mbps total throughput, with about a 2-to-1 difference between down and uplink throughput as the IxChariot plot shows. Although there is variation in the downlink throughput, there is no "battling" for dominance. Airtime is clearly managed so uplink gets more throughput than downlink (you would think the opposite would be the case).
NETGEAR R7800 four stream throughput - simultaneous up/downlink
Separate down and uplink tests yielded 839 and 690 Mbps, respectively. Downlink shows much lower variation than uplink. Oddly, in separate tests, downlink has higher throughput than uplink.
NETGEAR R7800 four stream throughput - up and downlink
To see if the single connection was limiting throughput, I raised the number to eight. This increased total throughput to 934 Mbps for downlink...
NETGEAR R7800 four stream throughput - downlink 8 connections
...and 937 Mbps uplink. These numbers tell me the single Gigabit link was saturated, capping throughput. For both directions, throughput distribution among the connections is remarkably uniform.
NETGEAR R7800 four stream throughput - uplink 8 connections
160 MHz Bandwidth
The R7800 is the first product on the market to support 160 MHz bandwidth mode. Since there is not actually 160 MHz of contiguous bandwidth in the 5 GHz band available in consumer routers today, this is implemented as 80 MHz + 80 MHz.
160 MHz mode enables devices to basically double their maximum link rate. So a 2x2 STA 802.11ac STA that supports 160 MHz mode can have a maximum link rate of 1733 Mbps vs. the 867 Mbps it would normally have. Of course, like many of 802.11ac's high-bandwidth tricks, higher 160 MHz mode bandwidth requires a strong signal to work effectively.
To test 160 MHz mode operation, I asked NETGEAR to supply a device supporting 160 MHz mode. These are apparently hard to come by because NETGEAR shipped a second R7800 router and special firmware to make it operate as a 2x2 device.
The setup was the same used for the 4x4 maximum link rate test. The only difference was that the bridge mode router had the special firmware loaded. I ran two sets of tests: one with the Enable HT 160 box in Advanced Wireless Settings checked on both router and bridge; the other with both unchecked. As noted earlier, the R7800's default is Enable HT 160 unchecked.
The IxChariot composite plot below shows 5 GHz downlink tests run with and without 160 MHz mode. I confirmed the link rates with traffic running for each set of tests. Highest link rate observed with 160 MHz mode disabled was 780 Mbps and 1560 Mbps with 160 MHz mode enabled. Throughput gain from 160 MHz mode was only 29%.
NETGEAR R7800 160 MHz test - downlink comparison
Running the tests in the uplink direction eked out a bit more throughput gain with 160 MHz mode, about 33%.
NETGEAR R7800 160 MHz test - uplink comparison
I also ran simultaneous up and downlink tests with 160 MHz mode disabled...
NETGEAR R7800 160 MHz test - simultaneous up and downlink - normal
...and enabled. This test produced only 17% higher throughput.
NETGEAR R7800 160 MHz test - simultaneous up and downlink - 160 MHz
As with MU-MIMO, I'm sure there is plenty of tuning to be done to get the most out of 160 MHz mode. Once again, there is plenty of time to do this since I know of no devices in the wild with working 160 MHz mode and neither NETGEAR nor QCA volunteered a list of any.
The Ranker Performance Summary below shows the R7800's weakest spot is 5 GHz uplink range, where is ranks #3. All other sub-rankings are either first or second place.
Ranker Performance Summary comparison
Judging by CES 2016 introductions, MU-MIMO is moving into the mainstream as a feature in higher-end routers. 160 MHz may not be far behind, but will take a bit longer. Too bad that device makers haven't gotten with the MU-MIMO program yet. If MU-MIMO is a standard feature on the latest smartphones and tablets, their makers sure aren't going out of their way to let us know.
If you're considering a MU-MIMO router today, your best choice would be an AC2600 class product based on Qualcomm / QCA devices. Broadcom's MU-MIMO is still in beta until this summer at the earliest. I have to hold off declaring which AC2600 class router provides the best total MU-MIMO throughput gain until I get my test hardware sorted out. But for use with non MU devices, NETGEAR's R7800 is our new top performance-ranked choice.