Heating locality and current drive efficiency of X-wave and O-wave ECH/ECCD from the lower field side are theoretically investigated for tokamak plasmas in the range of the electron temperature –22.5 keV and the density ne = 1.0– m−3, corresponding to the plasmas in the current ramp-up phase in fusion tokamaks. Performance of X-waves is better than that of O-waves up to keV, above which O-wave performance still improves with Te, while X-wave performance deteriorates with Te due to the absorption via second harmonic resonance before the waves penetrate into the fundamental absorption area at the plasma core. When Te increases to 10 keV, the cutoff density for X-waves increases by 15% beyond the cold plasma cutoff density.