Two major coronal mass ejections (CMEs) observed during the Whole Heliosphere Interval (WHI) are compared with the catastrophe (CA) and eruptive flux rope (EF) models. The objective is to test two distinct mechanisms for CMEs by mod- eling these well-observed CMEs and comparing predictions of the theories and observed data. The two CMEs selected for this study occurred on 25 March and 5 April 2008, respectively. For the 25 March event, an M 1.7 class flare, a filament eruption, and hard X-ray (HXR) and soft X-ray (SXR) emissions were observed during the CME onset. The observed CME kinemat- ics and SXR light curve of this event are found to be more consistent with the EF model than with the CA model. For the 5 April event, the SXR light curve shows multiple enhancements, some of which temporally coincide with successive side loop brightening and multiple foot points at the source region after the eruption. The physical connection between the side- loop multiple brightenings and the eruption cannot be determined from the data. Both models produced observationally consistent kinematics profiles, and the EF model correctly predicted the first emission enhancement. Neither model includes multiple brightenings in the formulation.