The ZyXEL NBG6815 is not Wi-Fi certified. All tests were run using our Version 8 Wireless test process with V1.00(ABBP.1)C0 firmware loaded. The router was first reset to factory defaults then Channel 6 with 20 MHz bandwidth mode was set for 2.4 GHz and Channel 153 and 80 MHz channel width for 5 GHz. The NETGEAR R7000 bridge mode standard test client was connected using WPA2/AES encryption.
The router was centered on the chamber turntable in its normal vertical position.
Comparing average 2.4 GHz throughput for the NBG6815 and all tested AC2350/AC2400 class routers tested shows the ZyXEL running toward the bottom of the pack for downlink and uplink.
2.4 GHz average throughput comparison
The same comparison of average 5 GHz throughput shows the NBG6815 second from the top for downlink, but in the bottom position for uplink.
5 GHz average throughput comparison
For 2.4 GHz downlink, the NBG6815 started out with lower throughput at lower attenuation than the other two routers but exceeded the NETGEAR R7500 from about 15 dB to 27dB. Thereafter, the NETGEAR and ZyXEL tracked each other through the rest of the range. The ASUS RT-AC87U is clearly the best of the bunch for downlink.
For 2.4 GHz uplink, the three routers have very similar performance except for 0 to 18 dB tests, where the ASUS again clearly leads.
2.4 GHz Downlink and Uplink Throughput vs. Attenuation
For 5 GHz downlink, the NETGEAR R7500V2 starts out with a clear throughput advantage over the other two routers. But from about 18 dB of attenuation out to the end of the test, all three routers tracked very closely. Both the NETGEAR and ZyXEL dropped their connections with 3 dB less attenuation than the ASUS.
For 5 GHz uplink, the NBG6815's plot is below and to the left (poorer throughput) than the other two routers for the entire range. As with the downlink tests, both the NETGEAR and ZyXEL dropped their connections with 3 dB less attenuation than the ASUS.
5 GHz Downlink and Uplink Throughput vs. Attenuation
Analysis by Tim Higgins
Although long overdue, we're finally getting our first look at Quantenna's MU-MIMO performance! Now that MU-MIMO has a standard test procedure and its own set of charts, comparisons are much easier.
All MU-MIMO enabled products we've tested, except Linksys' EA7500, have 4x4 5 GHz radios. So while the chart shows AC2200, AC2350 and AC2600 classes, all can be fairly compared. And that comparison shows the NBG6815 not measuring up very well for average throughput
MU-MIMO Average Throughput comparison
SU (single user) MIMO tests are a good indication of how efficent routers are at serving multiple STAs. Ideally, total throughput should be divided among active STAs, with none lost. Unfortunately, the ZyXEL doesn't do very well in this test, either. It beats only TP-LINK's Archer C2600, which has a troubled MU-MIMO implementation.
SU-MIMO Average Throughput comparison
The MU, SU Throughput Difference lets you quickly zero in on products with better MU-MIMO throughput gain. Clearly with a value of -10, the ZyXEL has problems.
Average MU, SU Throughput difference
The MU, SU Difference vs. STA plot shows worse or at best the same total throughput for MU vs. SU for the NBG6815.
MU, SU Throughput difference
The SU-only plot shows a major contributor to the ZyXEL's poor showing. The two NETGEAR plotlines are what SU throughput is supposed to look like. Clearly, the NBG6815 does not share throughput very well above four STAs (devices).
SU Throughput vs. STA
The conclusion I draw from this is that the NBG6815's MU-MIMO implementation is broken. And it doesn't look like the router will distribute throughput very evenly when the number of active STAs is above four.
Normally we include an analysis based on the Router Ranker. But since the NBG6815 is, and is likely to remain, the only AC2200 class router, it would not be helpful. Instead, here's the bottom line: there are lots better choices in MU-MIMO routers than the NBG6815.
Throughout the review, we've compared the NBG6815 to the #1 ranked (ASUS RT-AC87U) and #2 ranked (NETGEAR R7500V2). Of the four AC2350 class routers in our charts, only the R7500V2 supports MU-MIMO. The others have Quantenna 5 GHz radios, which still do not support MU-MIMO.
If MU-MIMO performance is important to you, we recently retested all of the MU-MIMO products in our charts and concluded:
"The NETGEAR R7800 is the best example of what you should expect from a MU-MIMO router. Total throughput gain peaks at three devices, then remains as close to that peak as possible as more MU devices are added. Some throughput decline is expected, but the slope should be as gentle as possible."
However, the NETGEAR R7800 is an AC2600 class router that will set you back around $250 - well above the $200 price tag on the ZyXEL NBG6815. But NETGEAR's R7500 v2 is a decent MU-MIMO enabled alternative and currently sells for less than the NBG6815.
If you want to spend less than $200 on a 4x4 router and MU-MIMO isn't important to you, you should consider the #1 ranked AC2350 class router, the ASUS RT-AC87U, currently priced around $190. If MU-MIMO is a must-have, the best current bets are the NETGEAR R7800 or NETGEAR R7500 v2, depending on your budget.