Dell's own self reporting on their website, I presume. I got an XPS15 a couple of months ago and I have no idea what crack Dell smoked to get that number. I don't have a problem with the battery life personally since I'm coming off a very old laptop which has about a 6 minute lifetime, so the 4-5 hours I can get is a breath of fresh air, plus I tweaked the battery to the "mostly plugged in all the time" setting which I think works by lowering the max charge limit to 80%, so most people will probably get more than I do (at least at first). But if you're used to getting 10 hours from an existing system you may be disappointed.

Are you guys seeing 15" MBPs with discrete GPUs really get 10 hours of battery life? I've got one at home and one at work, and moderate usage manages to kill them both in 4 or so hours a lot. Big difference from the 13", which consistently lasts longer for me. That GPU likes to switch on, and that screen is a big hog too.

What are you using that causes the discrete GPU to turn on? Install Gfxcardstatus to find out.

I get about 8 hours on my 2 year old 15 rMBP with Safari. Less than 4 hours with Chrome.

Interesting, haven't tried Safari. Chrome and Firefox are both big big culprits for flipping the GPU on for me.

Chrome and Firefox drain batteries really fast. When I use Chrome on my MBP, I have 2 to 4 hours less battery life compared to Safari. Google / the Blink developers really don’t care about draining the battery. It is infuriating because Opera, Vivaldi and other browsers using the Blink engine suffer from the same problem. Safari has come a long way, both in terms of battery savings and usability. I use Safari Technology Preview[1], which is the most up-to-date version of Safari. Apple releases an update every two to four weeks.

[1] https://developer.apple.com/safari/technology-preview/

Safari has improved dramatically in the past couple years. Give it a shot.

No, I don't even think 6-7 hours is bad unless I'm flying and even then most seats have plugs these days it's just a pain to have the cables all out. I just noticed the huge disconnect from the 17 hour claim.

Between Chrome and Photoshop my GPU seems to be on pretty much all the time on my MBP. I get probably 5-6 hours on it working unplugged(my power cable is usually at my standing desk and some days I'm lazier than normal so I get close to this before standing up again).

Not in European planes.

>Are you guys seeing 15" MBPs with discrete GPUs really get 10 hours of battery life?

I get close to 8 hours with a late 2013 MBPr 15".

Pulled it from their website. Should have said 'claims up to' like I did with the Surface Book.