the power supply is for charging the battery faster. the new magsafe 3 system can charge with more wattage than usb-c, as per the announcement. usb-c max wattage is 100 watts, which was the previous limiting factor for battery charge.

USB Power Delivery 3.1 goes up to 240 W (or, I should say, “will go up” as I don’t think anybody is shipping it yet)

USB-C 3.1 PD delivers up to 240watts.

That's with 2 connectors right? I have a Dell Precision 3760 and the one connector charging mode is limited to around 90W. With two connectors working in tandem (they snap together), it's 180W.

The connectors never get remotely warm .. in fact under max charge rate they're consistently cool to touch, so I've always thought that it could probably be increased a little bit with no negative consequences.

Single connector, the 3.1 spec goes up to 5A at 48V. You need new cables with support for the higher voltages, but your "multiple plugs for more power" laptop is exactly the sort of device it's designed for.

It was announced earlier this year, so not in wide use yet. PDF warning: https://usb.org/sites/default/files/2021-05/USB%20PG%20USB%2...

I’ve not seen any manufacturer even announce they were going to make a supported cable yet, let alone seen one that does. I might’ve missed it though. This will only make the hell of USB-C cabling worse imho.

The USB Implementers Forum announced a new set of cable markings for USB 4 certified cables that will combine information on the maximum supported data rate and maximum power delivery for a given cable.

Currently I think there aren't any, and the MBP will only get its full 140W capacity using the magsafe cable.

Color me skeptical.

I believe you (and Apple) that the battery can be charged faster, but I am currently rendering video on an M1 MBP. Its power draw: ~20 Watts.

That's a lot of charging overhead.

The 16” has a 100wh battery, so it needs 100w of power to charge 50% in 30 minutes (their “fast charging”). Add in 20w to keep the laptop running at the same time, and some conversion losses, and a 140w charger sounds just about right.

That actually sounds on the money. I hope you're right!

The other end of the new MagSafe is usb-c, which gets plugged into the power adapter.

Sure, but it's an Apple cable plugging into an Apple socket. They don't have to be constrained by the USB-C specs and could implement a custom high power charging mode. In fact I believe some other laptop manufacturers already do this.

They support fast-charging the battery to 50% in 30 minutes. That's probably the reason for the beefy charger.

I'm surprised the fast charger isn't a separate purchase, a la iPhone.

I’m not particularly surprised. They have little to prove with the iPhone, but have every reason to make every measurable factor of these new Macs better than both the previous iteration and the competition. Throwing in a future-model-upsell is negligible compared to mixed reviews about Magsafe 3 cluttering up reviews they otherwise expect to be positive.

Yeah I'd prefer that. Converted everything to quality 6ft braided usb-c cables, bought a separate multiport charger. Will have to sell original one...

Just in case people missed it - the magsafe cable connects to the power supply via usb-c. So (in theory) there's nothing special about the charger that you couldn't do with a 3rd party charger, or a multiport charger or something like that.

MagSafe was a gimmick for me - disconnects far too easy, cables fray in like 9 months, only one side, proprietary and overpriced. Use longer cables and they will never be yanked again. MBP is heavy enough that even USB-C is getting pulled out on a good yank.

I briefly had an M1 Macbook Air and the thing I hated the most about it was the lack of Magsafe. I returned it (needed more RAM) and was overjoyed they brought Magsafe back with these and am looking forward to having it on my new 16" You can also still charge through USB C if you don't care for Magsafe.

Might be a power limitation. I have an XPS 17 which only runs at full performance and charges the battery with the supplied 130W charger. USB C is only specced to 100W. I can still do most things on the spare USB C charger I have.

With the latest USB-PD standard that was announced in May, up to 240W is supported

I have a top-spec 15” MBP that was the last release just before 16”. It has 100W supply and it’s easy to have total draw more than that (so pulling from the battery while plugged in) while running heavy things like 3D games. I’ve seen around 140W peak. So a 150W supply seems prudent.