Wireless Display adapter v2 defaulting to 802.11b with intel AC-8260

Question

Hi, my wireless display adapter v2 keeps negotiating to use 802.11b when I project using an intel wireless-ac 8260.

Display adapter:

V2 running firmware 2.0.8372

Laptop 1:

Lenovo X1 Carbon Gen 4. i5-6300u with wireless card intel ac-8260 (driver 19.70.0.5) and intel hd graphics 520 (driver 21.20.16.4550)

Windows 10 1703

Laptop 2:

Lenovo X1 carbon gen 4 i5-6300u with wireless card intel ac-8260 (driver 19.70.0.5) and intel hd graphics 520 (driver 21.20.16.4550)

Windows 10 1607

Laptop 3:

Dell Precision 5520 with i7-7820HQ with wireless card dell/qualcomm/atheros DW1820 (driver 12.0.0.307) and intel HD graphics 630  (forgot the driver version)

Windows 10 1607

Laptop 4:

Lenovo P50 with i7-6820hq and wireless card intel ac-8260 (driver 19.20.3.4), intel hd 530 (20.19.15.4483), quadro m1000m with driver 21.21.13.6909

Tablet 1: 

Surface pro 3 with i5-4300u with the marvell-avastar wireless card (latest firmware)

Windows 10 1703

Tablet 2:

Surface pro 3 wiht i7-4650u with the marvell-avastar wireless card (latest firmware)

Windows 10 1703

Tablet 3:

Lenovo X1 tablet (g1) with m7-6y75 with intel ac-8260 (driver 19.70.0.5) and intel hd graphics 515 (driver 22.20.16.4718)

Windows 10 1703

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Devices tested at about 2m max from the display adapter. I'm reading the negotiated network protocol by looking at task manager -> performance -> wifi direct network adapter

Laptops 1, 2 and 4 with the intel ac-8260 seem to only connect at 802.11b which is ok for basics but when trying to mirror 1080p video, the limit of 11 mbps is too low.

Laptop 3 using a dell/qalcomm/atheros card negotiated at 802.11n which I am happy with. I would have hoped for AC but this will provide enough bandwidth.

Tablet 1, the i5 surface sometimes negotiates 802.11g, 802.11a, and sometimes 802.11ac depending on what wireless network I have it on. I don't mind a's bandwidth but the range improvements of ac are preferred.

Tablet 2, the i7 surface negotiates 802.11ac all the time.

Tablet 3, with intel ac-8260 keeps negotiating b.

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What I don't get is whether this is an intel driver problem (I have the latest drivers). I understand MS would have tested the marvell-avastar adapter of the sp3 pretty well with the surface display adapter, and I can see it is capable of AC. Qalcomm seem to have done a good job and have the adapter negotiating N. Intel's 8260 seems to be 'falling back' to the basic 802.11b. Is there a log to view the negotiation process between laptop and display adapter?

**Is there a known issue with AC-8260 refusing to negotiate AC and falling back to b?**I did observe that "intel WiDi" flashed up shortly after connecting to the adapter on the intel-wireless devices.

Can MS please consider upping the fallback from 802.11b to 802.11g, which will at aid/fix the bandwidth problems trying to send 1080p video?

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Edit:

powershell's get-netadapter says I am getting a linkspeed of 72Mbps (which to me means faster than G) which conflicts with what task manager says. I am now thinking that the adapter is properly negotiating something faster than what task manager reports.

Answer 1

It might be worthwhile asking the question about the AC-8260 in the Lenovo

forums as you have at least a couple of Lenovo devices. And definitely in the

Intel forums (where there are threads about the speed of this chip in general).

The negotiation of speeds is part of the Miracast/WiFi protocol and isn't

something MS can change.

>>Is there a known issue with AC-8260 refusing to negotiate AC and falling back to b? I did observe that "intel WiDi" flashed up shortly after connecting to the adapter on the intel-wireless devices.

>>

>>

>>

>>Can MS please consider upping the fallback from 802.11b to 802.11g, which will at aid/fix the bandwidth problems trying to send 1080p video?