I have Vivid 200 fibre, SuperHub 3.0 Wifi box is in the living room. And I'm always sitting in the kitchen. Between me and wifi box is only one wall(one wall Karl)- but speed is so slow... i have tried to restart the box,nothing helpd.
You will need to test the actual internet connection speed wired directly to the hub with a Cat 5e cable or better with a device equiped with a gigabit ethernet network card. Wireless is just too unreliable to test the actual internet speed accurately as it is affected my many external factors like Range, Client hardware, Interference and the Topography of your home. For example, a stud partition wall will absorb about half of the wireless signal's strength.
If you are getting headline wired speeds during the day and during the evening peak, then it loos like a wireless problem as opposed to a problem with your internet connection. Once the problem is confirmed as a wireless problem then we can investigate further.
The laptop should have a gigabit ethernet adapter from what specs I have seen, so should be capable of 200Mbps
What wireless adapter does the laptop have? According to the Dell website the wireless adapter is an option ranging from single stream wireless N adapters to the new wireless AD adapter. I suspect it is a wireless AC adapter from the specs of the "off the shelf" laptops I have seen. If confirmed that is an AC adapter then 200Mbps should be achievable close to the router with a clear line of sight.