I have had my Dell XPS 13 for almost half a year now. It’s the 2015 model numbered 9350. Ever since I got it, the WiFi has had issues. It’s dropping packets left and right and especially when placed on uneven surfaces like my lap or a carpet. I think it also has something to do with heat because it seems to take a while to show up after the computer is initially powered on. The issue worsened with time to the point where I simply can’t use it on my lap anymore.
I am far from alone with this issue. A simple Google search shows many people complaining about some variation of the same. Luckily, some of them actually figured out the culprit and it’s the Broadcom WiFi card. Apparently some models come with an Intel WiFi card that works perfectly fine. In the 2016 model they went ahead and completely replaced the faulty Broadcom card with Killer card across all models.
For whatever stupid reason, I decided to call Dell Support before just replacing the card myself. They were predictably useless and wasted two and a half hours of my time. Tier 1 took two hours of blindly following steps from a piece of paper. Tier 3 actually tried some advanced WiFi settings I never heard of, but that failed too. And then they saw my VirtualBox network adapters. They immediately jumped to conclusions that I’m sharing my connection with other computers (huh?) and that I need to disable them. So we disabled them and then instead of running an actual test like moving the laptop to an uneven surface, they ran one pingtest.net and decided that one passing test means they fixed the issue. I hung up.
More angry at myself for wasting my own time than Dell Support doing their jobs, I went ahead and purchased:
- Intel WiFi card 7265NGW
- Screwdriver set with Torx T5 because why make things easy to repair?
- Plastic pry tools because Torx is not hard enough
Once everything arrived, I followed the service manual and installed the new card in less than 10 minutes. With the right tools in hand, it was really simple and only cost $40. No need to wait 10-14 days for Dell to repair my laptop and no need to waste my time convincing technical support that it’s a hardware issue and another Broadcom won’t help.
Needless to say the WiFi is finally working perfectly fine on any surface.
kichik's blog 
“In the 2016 model they went ahead and completely replaced the faulty Broadcom card with Killer card across all models.”
The Killer card that I got with my 2016 XPS sucks ass, too. It never worked right, dropped under load, and the latest driver update made it lock up randomly (requiring full reboot) after sleep/hibernate. I’ve resigned myself to the fact that if a laptop doesn’t come with an Intel wifi card, I’m going to eventually have to replace it with an Intel wifi card.