INTEL WIRELESS-AC 9560 not working with channel 36 and 80MHz width

[SLeun6]

Hello,

I have observed a weird behavior when I'm connecting my device to an access point that is using channel 36 and 80MHz channel width.

Symptom

Client reporting 866Mbps data rate, but the access point tells me the client is running at 13Mbps.

Low throughput and the connection hangs intermittently:

C:\Users\slyh>ping 1.1.1.1 -t

Pinging 1.1.1.1 with 32 bytes of data:

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

Reply from 1.1.1.1: bytes=32 time=7ms TTL=57

Reply from 1.1.1.1: bytes=32 time=7ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

General failure.

Reply from 1.1.1.1: bytes=32 time=65ms TTL=57

Reply from 1.1.1.1: bytes=32 time=7ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

General failure.

General failure.

General failure.

Reply from 1.1.1.1: bytes=32 time=17ms TTL=57

Reply from 1.1.1.1: bytes=32 time=8ms TTL=57

Reply from 1.1.1.1: bytes=32 time=7ms TTL=57

General failure.

General failure.

Reply from 1.1.1.1: bytes=32 time=58ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

Reply from 1.1.1.1: bytes=32 time=7ms TTL=57

General failure.

General failure.

General failure.

Reply from 1.1.1.1: bytes=32 time=9ms TTL=57

Reply from 1.1.1.1: bytes=32 time=7ms TTL=57

Reply from 1.1.1.1: bytes=32 time=6ms TTL=57

Ping statistics for 1.1.1.1:

Packets: Sent = 28, Received = 19, Lost = 9 (32% loss),

Approximate round trip times in milli-seconds:

Minimum = 6ms, Maximum = 65ms, Average = 13ms

Observation

The client works fine when it's connecting to networks which are using any channels other than ch. 36-48.

It will also work if I force the router to use 20MHz/40MHz channel width (even if it's using ch. 36) or set the option "Channel Width for 5GHz" to 20MHz on the client side.

The system is running Windows 10 1803, I have tried driver version 20.40, 20.50, 20.80 and the problem insisted. I have also tried to connect to access points from different brands (including Ubiquiti, EnGenius and Aruba). I would like to avoid any hardware fix as the chip is soldered on the motherboard and it will be a mess if I have to get the board repaired or exchanged.

[idata]

Hello slyh,

Thank you for posting in our Intel ® Community.I understand that you are facing performance issues when connecting your Intel® Wireless-AC 9560 to an access point using the channel 36 (80MHz channel width)We would like to investigate further the issue that you are experiencing.Please provide me with the current settings of your device through a report created by our https://downloadcenter.intel.com/download/25293/Intel-System-Support-Utility-for-Windows-?product=91600 Download Intel® System Support Utility for Windows*To attach a file, you must click the "Attach" option on the bottom right-hand corner of the response box.Also, even if you already have the latest wireless drivers, we would like to discard any possibility of a driver corruption during the past installation.Please perform a clean installation of the Wireless Drivers by following https://www.intel.com/content/www/us/en/support/articles/000022173/network-and-i-o/wireless-networking.html these steps.https://downloadcenter.intel.com/download/28143/Intel-PROSet-Wireless-Software-and-Drivers-for-Windows-10?product=99446 Here you will find our latest drivers.I hope to hear from you soon.Regards,Diego Sanchez Campos.

Intel (R) Customer Support Technician

Under Contract to Intel (R) Corporation

[SLeun6]

I have attached the report that you have requested.

Driver has been reinstalled according to the guide. Although it is unlikely to be a corrupted driver as I have done several clean Windows installation.

[SLeun6]

FYR, I have generated a report with the manufacturer provided driver.

[idata]

Hello slyh,

Thank you for your response.Please go ahead and try our https://www.intel.com/content/www/us/en/support/articles/000024678/network-and-i-o/wireless-networking.html Recommended Settings for 802.11ac ConnectivityAlso, is there any specific reason for using those specific channels?I hope to hear from you soon.Regards,Diego Sanchez Campos.Intel (R) Customer Support TechnicianUnder Contract to Intel (R) Corporation

[SLeun6]

The settings are the same as recommended one. Which can be verified by the SSU log.

is there any specific reason for using those specific channels?

I have no control over channels that the campus or public wifi use.

[idata]

Hello slyh,

Thank you for your response.We are currently investigating more about your case and the issue that you reported.I will post you back as soon as possible.Regards,Diego S.

[idata]

Hello slyh,

Thank you for your patience.In this case, based on the 802.11ac channel listing, the only supported Channel Width for the channel 36 and 48 is 20 MHz.For any other channel that you might be using, please use this table as a reference: This explains the issue that you are encountering as the 80 MHz Channel Width is reserved only for the channels 42, 58, 106, 122, 138, 155 Please let me know if you have any other concernRegards, Diego Sanchez Campos.Intel (R) Customer Support TechnicianUnder Contract to Intel (R) Corporation

[idata]

Hello slyh,

We just wanted to double check if you need further assistance?I hope to hear from you soon.Best Regards,Diego S.