XPS 13 Severely Reduced Wifi on Battery

Thanks for that useful input.

Wow. I apologize for the multiple posts. I guess it required moderator approval but wasn't saying anything on my side, and then the moderator approved all of them.

The multiple posts were not a problem for me. I appreciate the input. I've learned a bit during this exchange and deeper look at the whole wifi energy saver protocols. I also discovered that different speed test options react differently to this situation. I was originally using MegaPath (originally the speakeasy speed test) that I've been using for years as a speed test. lt shows the severely degraded speed on battery. However, the speed test from Ookla (I use their app on my phone to check speeds) shows comparable speeds on battery and AC. As I uderstand in, the energy saver approach calls for the router to accumulate data and then transmit that in bursts as the laptop powers the exchange on and off. If I do indeed understand this correctly (at least at a general level!), perhaps older speed tests see those suspended periods as just slow segments that then bring the average way down. Is that possible?

Thanks

Tom

As far as I am aware, there is no accumulating and transmitting in bursts from any power saving technology. That would be fairly disastrous for gaming, streaming, or any other real-time usage.

As far as the speed tests go, I couldn't tell you why one showed the speed difference while another did not. I usually point users to Ookla's speedtest.net and/or testmy.net. The difference may be in the size of the file used for testing, or possibly the number of samples. If you are getting incosistent results, try taking 5 tests from one and 5 tests from another, without changing  anything, and see if they even out. You should probably also clear your browser's cache, as that might be affecting the tests for those particular websites.

I may be misunderstanding, but I was basing my comment on this passage in the MS link you provided:

"When the mobile PC is running on battery power, the wireless network adapter is configured to use Medium Power Saving mode. This uses the 802.11 power save mode.

When an 802.11 wireless network adapter that is set to use power save mode wants to enter a sleep state, the adapter indicates this intention to the wireless AP. The adapter does this by setting the power save option in its packets or in the 802.11 frames that it sends to the wireless AP. In this scenario, the following behavior should occur:

When the wireless AP receives the frames that have the power save option set, the wireless AP determines that the client network adapter that sent the frames wants to enter a power saving state.  

The wireless AP then buffers packets that are destined for the client network adapter.

When the radio of the client network adapter turns on, the client network adapter then communicates with the AP to retrieve the buffered packets.

This behavior enables the wireless network adapter to use less power and to wake up periodically at the correct time to receive network traffic from the AP."

Well, yes and no.

It won't buffer data from client to AP. It will only buffer frames that are coming from the AP to the client. Frames going from client to AP will always cause an instant "on" state, or should. So, as long as you are, for instance, browsing, or gaming, or streaming, you are going to be in an "on" state, or should be, as your client machine is going to be sending a "ping" type signal to keep that from happening.

The only buffering that will happen is when the client goes inactive. If everything is working properly, the client will notify the AP that it has gone inactive, and the AP will buffer anything from that point on, until the AP wakes again. Therefore, unless it's malfunctioning, the power saving mechanism shouldn't affect  your speed tests.

It's not a constant buffer, constant on-off thing, so much as an automatic mini-sleep state. The waking periodically is to address the fact that not all traffic that is routed to a machine will be requested by the machine, so it will need to wake periodically to check for frames coming from the router, as the router's buffer isn't very large. 

That's how everything is supposed to work. Microsoft doesn't seem to have much faith in the APs, though, or at least that's what they're telling us.

Thank you for taking the time for that substantive and clear explanation. I enjoy solving problems, but I really love learning new stuff along the way. :)

Tom

Solution:

Dear All, I have same issue on Dell Latitude and I find this solution its works!

Go to Control Panel\Hardware and Sound\Power Options\Edit Plan Settings\advanced power settings\wireless adaptor settings\power saving mode\on battery:change to maximum performance. This will solve your issues.

Thank you