Peak of the HXR emission as a function of the peak of the soft X-ray derivative (dSXR/dt) flux for the height CMEs events with an associated hard X-ray flare. Yellow points are associated with HXR in the energy band 25−100 keV and red points to HXR in the energy band 50−100 keV because they are X-class GOES SXR. The orange dashed line represents the best fit for the data where we excluded the extreme yellow point with high HXR_max and low dSXR/dt_max. The corresponding Eq. (5) have a CC of 0.80.