New Ubuntu Laptop and wifi speed issue
I've just bought a new laptop running linux/ubuntu and experiencing wifi speed issues which I don't have with other devices, including another laptop running ubuntu. The problem I have is that the speed is fine when in the same room as the router but when I go upstairs the speed drops off dramatically. I have 250Mbs broadband and upstairs the speed can be down to 10-20Mbs. Other devices in the same location can get about 80Mbs.
Investigating the wifi signals using LinSSID I've found other wifi signals nearby on channel 11 2.4Ghz so I was wondering whether the issue was due to this. My laptop provider said that the wifi "card" in the laptop is low powered and the the clash of channels could be the issue. So in order to diagnose the problem I decided to change the channel from 11 to 6 on the 2.4Ghz connection. I have a hub 3 and had to Disable Channel Optimization to do this. However, it seems to have made things worse doing this.
Before I start looking into ubuntu/linux configuration, or returning the laptop, does anybody have any ideas as to what might be causing this laptop to lose its wifi speed, or maybe configure the router better.
Thanks in advance