Image credit: Ruckus Wireless
After 160 MHz Wi-Fi Channels: Friend or Foe? posted, I heard indirectly from some folks in the Wi-Fi biz that some of the results were not as they would expect. The most notable was the 867 Mbps uplink rate for a 160 MHz wide channel. I noted this in the article, but didn't know the cause.
Well, it turns out there was a bug in the octoScope Pal firmware that caused it to function at 80 MHz bandwidth on uplink only, even when it was set to 160 MHz mode. So I installed a bug-fixed version and reran the maximum throughput tests. Here is the original downlink plot...
Maximum throughput - 80 vs. 160 MHz channels - downlink
160 MHz AVG = 943 Mbps 80 MHz AVG = 682 Mbps
... which looks a lot like the retested results. I'd expect this, since downlink (Pal receive) link rate alternated between 1560 and 1733 Mbps.
Maximum throughput - 80 vs. 160 MHz channels - downlink - RETEST
160 MHz AVG = 943 Mbps 80 MHz AVG = 622 Mbps
Uplink was different, as we should expect. Here's the original plot, showing just about equal results for 80 and 160 MHz channel widths...
Maximum throughput - 80 vs. 160 MHz channels - uplink
160 MHz AVG = 707 Mbps 80 MHz AVG = 677 Mbps
...and here is the retest, which shows more than 30% higher throughput using a 160 MHz channel.
Maximum throughput - 80 vs. 160 MHz channels - uplink - RETEST
160 MHz AVG = 937 Mbps 80 MHz AVG = 709 Mbps
So yes, you should see higher throughput in both directions when using 160 MHz channels. I apologize for the error.
The other main chatter I heard was about the poor results using the Intel AC 9260 as STA. The comments implied there is incompatibility between the Intel AC 9260 and Qualcomm QCA9984 5 GHz radio used in the NETGEAR R7800. To my knowledge, this is Qualcomm's only AC device that supports 160 MHz bandwidth mode.
I also found that rebooting the NETGEAR R7800 could improve link rates and smooth out throughput when things looked hinky operating in 160 MHz bandwidth mode.
So I went back and reran throughput tests between the Intel STA and NETGEAR router. I ran four tests in each direction with HT160 mode enabled in the NETGEAR and with it disabled. I used the same (latest) driver and notebook as before (Dell XPS13 9350 running Windows 10, 184.108.40.206 driver). Here's the downlink retest...
Intel AC 9260 - 160 MHz B/W - Downlink - RETEST
Run1 AVG=847 Mbps Run2 AVG=774 Mbps Run3 AVG=848 Mbps Run4 AVG=944 Mbps
and here's the original test. There's obviously still some instability.
Intel AC 9260 - 160 MHz B/W - Downlink
Run1 AVG= 402 Mbps Run2 AVG = 941 Mbps Run3 AVG = 941 Mbps Run4 AVG = 926 Mbps
Here is the uplink retest...
Intel AC 9260 - 160 MHz B/W - Uplink - RETEST
Run1 AVG=336 Mbps Run2 AVG=672 Mbps Run3 AVG=263 Mbps Run4 AVG=21 Mbps
..and the original.
Intel AC 9260 - 160 MHz B/W - Uplink
Run1 AVG= 382 Mbps Run2 AVG = 214 Mbps Run3 AVG = 610 Mbps Run4 AVG = 605 Mbps
These results look worse than the original run, since only one of the four runs completed the shorter 65 second test. But on the other hand, maximum throughput was much higher, around 800 Mbps vs. 600 Mbps in the original run.
I attribute this to the fact that I verified that the R7800 was behaving itself in 160 MHz mode by checking throughput first with the octoScope Pal. So there does appear to be some incompatibility between Intel and Qualcomm when using a 160 MHz channel.