This article deals with the creep modulus process comparison of two structurally different materials. These are specific materials HDPE (high density polyethylene) and LDPE (low density polyethylene). These materials were chosen because of their shared monomer from which they were created and differ only in the chain shape. Subsequently these materials were beta radiation crosslinked at six various doses, which changed the inner structure for more complex measurement and the extensive description of the given topic. To obtain data Toledo DMA1 device of the company Metler and earlier data were used for use of knowledge. The results show if the radiation doses efficiency is higher for material with higher or lower density.