Bug caused by the current Intel AX201 driver on the device

Nov 1, 2019 12:34 GMT  ·  By

Surface Pro 7 is Microsoft’s latest and greatest in the Surface Pro lineup, and it comes with major improvements, including an important performance upgrade thanks to latest-generation hardware under the hood.

Surface Pro 7 was announced on October 2 and it went on sale on October 22 in the first markets.

This means customers are only now getting their hands on the new model, and by the looks of things, some have already found an issue affecting the network performance of the device when resuming from sleep.

Basically, what happens is the Surface Pro 7 Wi-Fi speed becomes extremely slow after waking from sleep despite everything working correctly before entering the standby mode.

Microsoft is yet to acknowledge the issue, but a closer look at the whole problem performed by several users revealed that the slowdown is caused by Intel’s AX201 driver version 21.40.1.3.

NOTE: Microsoft Surface Pro 7 comes with custom drivers developed by Microsoft in partnership with Intel. While you should be able to install the generic Intel AX201 drivers, you are NOT recommended to do so. Installing generic drivers could cause other problems and block you from returning to the custom drivers that Microsoft ships pre-loaded on the device.

So while reinstalling or updating the drivers seem to be possible workarounds, just don’t this because you could eventually hit other issues.

The workaround, however, is much simpler, and it involves changing the MIMO power saving mode in Windows.

Reddit user Wiidesire has an explanation for the bug and claims the whole thing happens because the 2x2 MIMO configuration in the Intel AX201 adapter means one of the two antennas available on the device does not exit the low-power state when resuming from sleep.

“The new Intel AX201 adapter has 2x2 MIMO, basically double the antennas for double the speed (if your router supports it). Now in standby Dynamic SMPS disables one antenna and the other antenna goes to a low power state. However the bug is that after waking up the device from standby, the second antenna is not activated and the other antenna remains in the low power state resulting in severely reduced speeds, higher latency,” they say.

Technically, you can change the MIMO settings by following the next steps:


Right-click Start menu > Device Manager > Network adapters > Right-click Intel AX201 > Properties > Advanced
In the list of options, select the one called:
MIMO power save mode
The drop-down menu on the right lets you change the settings of the MIMO power saving mode, and according to this workaround, there are two ways to go at this point, as it follows:
No SMPS = bug still happening, but only on rare occasions + higher power usage
Static SMPS = bug no longer happening, but MIMO is disabled, therefore slower Wi-Fi speeds
As you can see, each option comes with its very own drawback, but fortunately, there’s another method to resolve at least one of them. Choose No SMPS and then follow this path to prevent the high power usage:
Windows 10 > Settings > System > Power & Sleep > When my PC is asleep and on battery power disconnect from network > Always
The high power consumption happens because the antennas of the device no longer enter a low power state during standby, as the network remains active. However, by disabling network access when entering standby, this is no longer required, which means the antennas are not needed anymore, therefore the power consumption issue is resolved.

Microsoft is yet to come up with a fix, but once a patch is available, these changes should no longer be necessary.