I did a bit of testing with my filter and there was barely any difference using an old ADSL filter and new VDSL filter faceplate.


Thats not to say its the same in all circumstances, but in my case, made no difference.
in fact the only difference was the Dynamic Line Management from BT kicking in and dropping my speed. It sees the loss of sync as a problem on the line and tries to adapt by lowering the speed to keep the service stable.