"Yes bare wires from the router."
What the hell are you doing?!
Also the speed bump was entirely coincidence, it is likely BT resolved the issue or that you messing with the wiring fixed something.
No such thing as a modem resetting everything perfectly.
Your old stats has no spare noise margin, hence it would have been impossible to jump speeds without a change to the line somehow ie fault fix.
I personally think when you connect these "bare wires" you had not solidly connected one of the pairs. That would half the speed.
Edited by ukhardy07 (Wed 08-Jun-16 07:53:00)