A comparative analysis of radiated power in relativistic magnetron is done using particle-in-cell simulations performed on Magic3d code developed by ATK Mission Systems. The Resonator with dielectric side-walls (DSW) is compared with no-side wall (NSW) configuration having same input parameters and resonator dimensions. Observations and comments have been made on the output power, obtained both axially and radially, taking into consideration π as well as 2π modes of operation for both configurations. The DSW assist in π-mode operation at 3.3 GHz and delivers radial peak power output of ~2.5 GW, which is more than ~1.5 GW, the radial peak power for the NSW case. The NSW case operates in dominant 2π mode (radially) at 5.68 GHz with axial power radiated at dominant π-mode frequency. The electron kinetic energies and their distribution in the cavity are discussed together with the dynamic behavior of particles, which result in spokes formation.