WiFi Latency Spikes Caused By Powersaving - How to disable?

[ryannathans]

Hi all

I've spent a week tracking down a VERY annoying problem. Every few seconds, my WiFi (any band/channel) on my desktop computer encounters packet loss or high latency. Here is a screenshot pinging my default gateway:

I used to get 1-2 ms all day long, but, recently this has started happening. Even during downloads or latency-critical applications. Sometimes it spontaneously fixes itself for a few minutes/hours but it keeps occurring.

But I found the culprit, finally.

The powersaving flag comes on VERY BRIEFLY for a second or so during each ping spike.

How the heck do I fix it? I'm on a desktop PC running Windows 10 Pro 64bit 1809 (17763.557). All the power saving settings I can find are set to maximum performance. E.g.

Please help

 

[Val D.]

Check in Computer -> Manage -> Device Manager -> Nertwork Adapters -> "Your Adapter" -> Properties -> Power Management -> Allow the computer to turn off this device to save power

 

[ryannathans]

Check in Computer -> Manage -> Device Manager -> Nertwork Adapters -> "Your Adapter" -> Properties -> Power Management -> Allow the computer to turn off this device to save power

It seems this tab doesn't exist anymore? In fact, this tab doesn't seem to exist on any device in device manager anymore

 

[Val D.]

It seems this tab doesn't exist anymore? In fact, this tab doesn't seem to exist on any device in device manager anymore

If this is the only PC on your network with the issue, then check the power management on that PC. I would start checking BIOS settings first, then move to OS settings. Do you see Computer -> ACPI x64-based PC in your Device Manager? Does it say "This device is working properly" in Properties? Try to re-install the drivers by removing the devices and "Scan for hardware changes". Sometimes helps.

 

[ryannathans]

I have reinstalled the driver for my network adapter, tried a different version of driver and also confirmed ACPI x64 based PC is working correctly I device manager. The problem persists on all tested drivers.

Interestingly, the same problem occurs on another desktop computer in the house (but not on my laptop). Both running the same version of Windows, but this is the only similarity. All hardware is different. The same problem also occurs with the on board wifi adaptor in my desktop PC, as well as the PCIe one pictured above.

 

[Val D.]

Any power saving features enabled on the router? Any changes in Wireless -> Professional section?

 

[ryannathans]

I have the ASUS RT-AC5300 running merlin 384.12. Yesterday I performed a full reset (reset NVRAM, JFFS, initialized defaults). I have not modified the professional section and I am not aware of any power saving features that I can modify on the router

 

[Val D.]

I would try to change two things on the router in Wireless -> Professional:

- lower the DTIM Interval to 1 (ASUS default is 3) and test again
This tells the devices when to wake up and receive the data

- disable WMM APSD (ASUS default is Enabled) and test again
This has to stop the devices to go to power save mode altogether

Mobile devices will drain the battery faster though after the change.

Post a screenshot of your settings in Professional.

 

[ryannathans]

I've had some success, approx. 20 minutes ago I did a "network reset" in Windows

I haven't seen any spikes in latency since - eg.

I've seen this problem resolve itself and reappear just hours later previously (when swapping wireless adapters for example). If/when this occurs again I will try your suggested changes.

Settings for your scrutiny

 

[ColinTaylor]

I've experienced very similar problems in the past with WiFi adapters that installed a "utility" that sits in the Windows notification area (system tray). Uninstalling that utility solved the problem.

 

[ryannathans]

I've experienced very similar problems in the past with WiFi adapters that installed a "utility" that sits in the Windows notification area (system tray). Uninstalling that utility solved the problem.

Thankfully ASUS have not made a utility for this network card - PCE-AC88

 

[Val D.]

If/when this occurs again I will try your suggested changes.

I would disable also:

- TX Bursting -> does not apply for N/AC networks, only B/G and with 1-5 devices
- MU-MIMO -> may reduce the throughput on some 2-stream N/AC devices
- Beamforming -> may cause compatibility issues in some devices and doesn't help much to improve the throughput
- NitroQAM -> Broadcom non-standard 1024-QAM support, not part of standard N/AC specifications

Your ASUS PCE-AC88 adapter is very fast. No need to push things to the limit. Other devices on your network may have issues.

 

[L&LD]

I've had some success, approx. 20 minutes ago I did a "network reset" in Windows

View attachment 18379

I haven't seen any spikes in latency since - eg.

View attachment 18380

I've seen this problem resolve itself and reappear just hours later previously (when swapping wireless adapters for example). If/when this occurs again I will try your suggested changes.

Settings for your scrutiny
View attachment 18382
View attachment 18381
View attachment 18383

After a very quick look at your settings, I would suggest disabling Universal Beamforming on all radios/bands and setting the 2.4GHz Preamble Type to Short.

(I'm assuming all the others are defaults).

 

[Val D.]

After a very quick look at your settings, I would suggest disabling Universal Beamforming on all radios/bands and setting the 2.4GHz Preamble Type to Short.

Preamble Type Long is the Default setting and is recommended for better compatibility with older devices and in areas with high interference and low signal. We don't know how many WiFi networks transmit around ryannathans. Why to change it? It doesn't make a big difference in performance anyway.

 

[L&LD]

Preamble Type Long is the Default setting and is recommended for better compatibility with older devices and in areas with high interference and low signal. We don't know how many WiFi networks transmit around ryannathans. Why to change it? It doesn't make a big difference in performance anyway.

Long Preamble type is for older devices, yes. From around 1997 to 1999.

Time to move on.

I have not worked on any network with current devices today that benefits from Long Preamble set.

 

[Val D.]

Long Preamble type is for older devices, yes. From around 1997 to 1999.

True, but even now most routers and access points come pre-configured with Preamble Type Long or Auto. Also, this setting has nothing to do with the issue ryannathans has.

 

[L&LD]

True, but even now most routers and access points come pre-configured with Preamble Type Long or Auto. Also, this setting has nothing to do with the issue ryannathans has.

That's why I suggest it be changed.

Never said it had anything to do with the issue here.

 

[ryannathans]

When I turned my PC on this morning the issue came back

I have adjusted the settings as suggested. Even with DTIM 1 and automatic power saving turned off (WMM APSD) the power saving latency issue still occurs on my desktop. Interestingly, with APSD turned off, all the phones still show P flag for power saving.

 

[ryannathans]

The Windows "network reset" fixed it again... for how long...

Maybe I will write a script to do a network reset every reboot

 

[ColinTaylor]

The Windows "network reset" fixed it again... for how long...

Maybe I will write a script to do a network reset every reboot

It sounds like you need to investigate the Windows side some more. Try running the task manager side by side with your ping window.