Return the machine if you can.  The problem you have is a common feature of that series of Dell machines. The Dell staff here does not acknowledge the problem and there is no guaranteed solution. Just search around the forum for yourself. Example: [URL]
Hi, i bought a new laptop couple weeks ago. the laptop as you can tell by the title is a dell inspiron 14 5000 series. It includes the driver is an Intel dual band wireless- AC 3160. The problem I have is that the internet is very slow. I am getting 1 mbps when i am in my room, but when i stand right beside the router i get my normal mbps which is 20 mbps. I have done some research on resolving this issue and the most common answers i have got is get a wired connection (if i am gonna do that, than i might as well get a pc) and get new driver (2x2). I have also changed my HT Mode to disabled which works, but the internet connection is still really bad (5 mbps). Now my action is to get a new driver but just to be sure is there any way to fix my internet connection?  I know its not the internet since the internet on the other laptops work perfectly fine. And i would return the laptop but unfortunately my 2 weeks are up.
New laptop (Dell Inspiron 14 5000 series) with really bad internet