Why does Wifi cost so much power?

[SaMMyS]

Since the release of new MacBook Pros I have a question in mind: why does Wifi cost so much power?
14inch MacBook Pro, "Up to 17 hours Apple TV app movie playback, Up to 11 hours wireless web". 16inch MacBook Pro, "Up to 21 hours Apple TV app movie playback, Up to 14 hours wireless web". Wireless web browsing cost 6-7 hours of battery life. Curiously, 13inch MacBook Pro/Air seems to be fine with wifi power consumption, only 3 hours battery drain with wireless web in a single charge.
We have seen wifi tech in years, why does it still cost so much power, which are saved by the efficient M1 Pro and M1 Max? or perhaps, like M1 in MacBook Air, it's a design choice by Apple?

 

[russell_314]

Since the release of new MacBook Pros I have a question in mind: why does Wifi cost so much power?
14inch MacBook Pro, "Up to 17 hours Apple TV app movie playback, Up to 11 hours wireless web". 16inch MacBook Pro, "Up to 21 hours Apple TV app movie playback, Up to 14 hours wireless web". Wireless web browsing cost 6-7 hours of battery life. Curiously, 13inch MacBook Pro/Air seems to be fine with wifi power consumption, only 3 hours battery drain with wireless web in a single charge.
We have seen wifi tech in years, why does it still cost so much power, which are saved by the efficient M1 Pro and M1 Max? or perhaps, like M1 in MacBook Air, it's a design choice by Apple?

Wireless web browsing is likely doing other stuff than continuous video playback. Like when you're surfing the web you have mouse clicks, open new pages, close old ones etc. Video playback is just one video playing. You can look at the bottom of the Apple page and it will say how they did the tests.

 

[tmoerel]

Wireless web browsing is likely doing other stuff than continuous video playback. Like when you're surfing the web you have mouse clicks, open new pages, close old ones etc. Video playback is just one video playing. You can look at the bottom of the Apple page and it will say how they did the tests.

Web browsing uses the CPU/GPU. Video replay on the other hand uses the internal video decoders which are very power efficient.

 

[SaMMyS]

Wireless web browsing is likely doing other stuff than continuous video playback. Like when you're surfing the web you have mouse clicks, open new pages, close old ones etc. Video playback is just one video playing. You can look at the bottom of the Apple page and it will say how they did the tests.

"The wireless web test measures battery life by wirelessly browsing 25 popular websites with display brightness set to 8 clicks from bottom."
Yeah, but they seems to be simple tasks, which we were doing 10 years ago...
The most intriguing thing is, 13inch MacBook Pro/Air seems to be fine, they can last 17-20 hrs, while 14inch MacBook Pro can last only 11 hrs. It seems to be a design choice by Apple, but why?

 

[SaMMyS]

Web browsing uses the CPU/GPU. Video replay on the other hand uses the internal video decoders which are very power efficient.

Right. It seems M1 Pro/Max drain so much more power than M1 in simple tasks like web browsing. perhaps because they have way more GPUs.

 

[JPack]

Because modulating and demodulating radio signals requires processing and this is done by the radio transceiver. The higher the frequency, the more processing required. This is why 5GHz Wi-Fi or mmWave 5G will always use more power than 2.4GHz Wi-Fi or mid-band 5G. In exchange, you get higher data throughput.

Some devices use Sub-GHz radios with a battery life measured in years.

This is entirely unrelated to CPU power consumption. iPhone/iPad/Mac will have significantly longer battery life if you play video locally instead of streaming.

 

[russell_314]

while 14inch MacBook Pro can last only 11 hrs.

So wait are you telling me that after browsing the web for "only 11 hours" I'll have to find an outlet... How am I supposed to keep up with my Facebook and Instagram that way ?

Seriously though it might be a little bit due to the WiFi module but if you're really curious you could use an Ethernet dongle and turn off WiFi. I suspect it has to do with making the computer change tasks every few minutes. It reminds me of how the old iPod used to last hours if you just let it continuously play but if you kept skipping tracks and picking new songs the battery would die much faster.

 

[yitwail]

Right. It seems M1 Pro/Max drain so much more power than M1 in simple tasks like web browsing. perhaps because they have way more GPUs.

Or because they have half the efficiency cores.

 

[Ifti]

Can anyone confirm if the MacBook still always favor's wifi over ethernet, even with both connected??

I currently have a 2019 16" i9 MacBook and have wifi connected so that I can unlock with my Apple Watch, use Airdrop from my iPhone, and so on.

I also have a TB to 10GBe adapter connected for 10GBe access to the home network and my NAS.

However, the system always favors wifi over ethernet. Ive changed the network connections list so ethernet is on top etc - tried everything I can think of and then gave up in the end. So now if I need to make a large data transfer I end up switching wifi off and starting the data transfer, then switch wifi back on - the system will continue that transfer with ethernet in this case.

Will see if this happens when my Mi Max MBP arrives - but anyone else have this??

Issue is discussed here, so I'm not alone!

How do I force Mac to use Ethernet connection when both WiFi and Ethernet are active?

I live in a 2-story apartment, with the router downstairs. WiFi is weak upstairs but I have an ethernet cable running to my Cinema Display. When I connect my Mac to the display, both WiFi and Ethernet (through the Cinema Display) are connected but I think the Mac using the WiFi as its primary...

forums.macrumors.com

 

[uller6]

Can anyone confirm if the MacBook still always favor's wifi over ethernet, even with both connected??

However, the system always favors wifi over ethernet. Ive changed the network connections list so ethernet is on top etc - tried everything I can think of and then gave up in the end. So now if I need to make a large data transfer I end up switching wifi off and starting the data transfer, then switch wifi back on - the system will continue that transfer with ethernet in this case.

Issue is discussed here, so I'm not alone!

How do I force Mac to use Ethernet connection when both WiFi and Ethernet are active?

I live in a 2-story apartment, with the router downstairs. WiFi is weak upstairs but I have an ethernet cable running to my Cinema Display. When I connect my Mac to the display, both WiFi and Ethernet (through the Cinema Display) are connected but I think the Mac using the WiFi as its primary...

forums.macrumors.com

I leave the Wi-Fi radio on but disconnected from a network on my iMac M1. I first connected to my Wi-Fi, then selected disconnect network and disabled auto join. I use Ethernet for internet, but keeping the Wi-Fi radios on lets me use airdrop/etc. I have no conflicts this way.

 

[JPack]

This spec from iPhone 13 basically tells you it's not the CPU/GPU, but Wi-Fi alone. Same video playback but significantly different battery life.

 

[yitwail]

This spec from iPhone 13 basically tells you it's not the CPU/GPU, but Wi-Fi alone. Same video playback but significantly different battery life.

That's an oversimplification, because OP questioned why the wireless vs Apple TV app difference is much greater in MBP14/16 than M1 MBA/MBP -- 6/7 hours vs 3 hours, whereas in the spec you cited, it's 4 hour difference in both columns.