Horse Power Loss ?

Good mentions here.

I was wondering about torque converters. How much power some loose over others. Efficent or not? How well they transmit the power. Etc. I guess.

Manual trannys do not have that problem, but the way the gears are cut, size gears, as in thickness and diameter all have to have a play.
Has anyone ever seen a list of the power loose's through certain manual trannys?
Some have to be better than others.