  During substructure formation in magnetized astrophysical plasma, dissipation
of magnetic energy facilitated by magnetic reconnection affects the system
dynamics by heating and accelerating the ejected plasmoids. Numerical
simulations are a crucial tool for investigating such systems. In astrophysical
simulations, the energy dissipation, reconnection rate and substructure
formation critically depend on the onset of reconnection of numerical or
physical origin. In this paper, we hope to assess the reliability of the
state-of-the-art numerical codes, PLUTO and KORAL by quantifying and discussing
the impact of dimensionality, resolution, and code accuracy on magnetic energy
dissipation, reconnection rate, and substructure formation. We quantitatively
compare results obtained with relativistic and non-relativistic, resistive and
non-resistive, as well as two- and three-dimensional setups performing the
Orszag-Tang test problem. We find the sufficient resolution in each model, for
which numerical error is negligible and the resolution does not significantly
affect the magnetic energy dissipation and reconnection rate. The
non-relativistic simulations show that at sufficient resolution, magnetic and
kinetic energies convert to internal energy and heat up the plasma. The results
show that in the relativistic system, energy components undergo mutual
conversion during the simulation time, which leads to a substantial increase in
magnetic energy at 20\% and 90\% of the total simulation time of $10$
light-crossing times -- the magnetic field is amplified by a factor of five due
to relativistic shocks. We also show that the reconnection rate in all our
simulations is higher than $0.1$, indicating plasmoid-mediated regime. It is
shown that in KORAL simulations magnetic energy is slightly larger and more
substructures are captured than in PLUTO simulations.
