I have uncovered a very strange issue and I am posting on here to see if anyone has any idea's as to why this happens.
Scenario: Internet running very slow, Youtube defaults to 144P

The mystery: It was running at 5 bars without any drop in signal at all when i checked previously, Youtube generally will stream at 1080P without the need to wait for buffering.
So I do some experimenting and remove the Pen drive in the port next to the USB WiFi dongle. Attempt speedtest
The speedtest - USB Pen drive next to WiFi dongle removed.

Surely that can't be the issue!!! So i plug it back in and perform a second speedtest.
Second Speedtest - USB Pen drive plugged back in next to the USB WiFi Dongle

Errr... yep it sure is!
So I appear to have found the issue.. just wondering if anyone can shed some light on why this happens? I for one am absolutely baffled. FYI i tried different USB ports aswell and the same effect is present.