A detailed quantitative study of the power absorption and predicted current drive, currently using Ehst-Karney parameterisation, will be presented on three tokamaks; ASDEX, DIII-D, and JET. The 2D full wave toroidal code TORIC is used to calculate the FW current drive efficiency weighted over the complete launched spectrum from the antenna. The code can simulate the complex physics of the efficiency and power balance of all three damping mechanisms as a function of plasma parameters and of n||. The code takes into account electron Landau damping of both the Fast Wave (FW) and Ion Bernstein waves and cyclotron damping at the fundamental and first harmonic. Results have shown that the current drive efficiency (normalized to the density) is machine dependent. The results have also demonstrated the importance of taking into account the full spectrum.