I remember you bringing this up in the past, but I think it's physically impossible that different PCBs could be running the game at different speeds.
This is not really true. There are several things that can happen to game boards to alter aspects of the game including sound speed/pitch, jumpman speed, height and length of jumps ect....
The wrong speed/pitch of the sounds are actually a pretty common repair on the PCB.
Usually the speed differences, like the sound differences we hear are pretty obvious and the skilled player would notice it immediately and anyone watching with any experience with the game would tell for sure. Its not a slightly difference speed, its a radically different speed, like 1.5 x or more or jumpman jumping all the way up the screen...
There was a similar thing that happened a few years ago when Dwayne set a WR on Nibbler and it ended up that the board was indeed running faster which allowed him to go through boards quicker. There have been a number of other games in the past that have been affected by subtle variations in voltage going into the board causing different behaviours. I recall a head to head Frogger battle between Pat and Don that ended because one of the boards keep acting up due to power issues.
Dwaynes issue was not a speed issue with the gameplay, it was an issue with the snake/screen regeneration speed. The game changed from board to board much faster giving him the ability to score many more screens per hour, the snake however moved at the proper rate once the board was generated.
I have never seen or heard of power related speed issues, though its technically possible. Usually power issues manifest themselves with random resets or sprite generation problems.
Looking at the video posted, it looks to be playing at the proper speed to me. Like Chris pointed out, aspect ratio, screen height/width can give the perception of game speed difference even if it is truly the same.
-Ken