Are you using Wi-Fi or Ethernet to connect to the internet?
If you are using Wi-Fi, it could very well be the card, but it could also be an outdated driver or other related network settings.
If you are using Ethernet, that is most likely integrated into the motherboard. In this case, it's most likely an outdated driver, or possibly even a bad Ethernet cable or connection.
I am assuming you meant Dell XPS 8960. There should be a label somewhere on the computer like this
Go to Dell Support https://www.dell.com/support/home/en-us?c=us&l=en&~ck=mn and enter your Service Tag, and then hit Search.
This will bring up your computer on Dell Support. You can now look at your computers Specifications by clicking "View product specs" in the Quick links.
You can also run some diagnostic tests for hardware issues, by clicking the Diagnostics tab.
Good luck my friend. 
