Evolution of the gas-relaxation parameter 2E_kin, gas/|E_pot|, which quantifies the dynamical state of the ICM for all four halos in the radiative (left) and non-radiative (right) simulations. In the radiative simulations, the high-redshift phase is dominated by frequent mergers and strong radiative gas cooling, which results in accretion and feedback events. In consequence, the ICM finds itself in an unrelaxed state in the forming protocluster. The non-radiative simulations display lower values of 2E_kin, gas/|E_pot| at high redshift due to the lack of feedback and cooling. Mergers at late times can be seen as upwards fluctuations in this quantity in both simulation runs.