This paper describes the analysis and experimental test of a discrete cascode GaN-GaN intended for high-frequency power converters. The proposed configuration takes advantages of both the high switching frequency capabilities of GaN-HEMTs and the robustness of depletion-mode GaN devices. Experimental tests compare the designed cascode GaN-GaN with an equivalent single enhancement-mode GaN device. The test is carried out in a boost converter of 400V-400W-30MHz. This power converter topology allows comparing both configurations in a demanding hard-switching condition. Experimental results suggest that at high-power and high-frequency the proposed cascode configuration can lead to performance improvements in the power converter selected for the test. These improvements arise from the reduced Miller-effect and the lower gate current of the cascode GaN-GaN.