  We have simulated the formation of a massive galaxy cluster (M$_{200}^{\rm
crit}$ = 1.1$\times$10$^{15}h^{-1}M_{\odot}$) in a $\Lambda$CDM universe using
10 different codes (RAMSES, 2 incarnations of AREPO and 7 of GADGET), modeling
hydrodynamics with full radiative subgrid physics. These codes include
Smoothed-Particle Hydrodynamics (SPH), spanning traditional and advanced SPH
schemes, adaptive mesh and moving mesh codes. Our goal is to study the
consistency between simulated clusters modeled with different radiative
physical implementations - such as cooling, star formation and AGN feedback. We
compare images of the cluster at $z=0$, global properties such as mass, and
radial profiles of various dynamical and thermodynamical quantities. We find
that, with respect to non-radiative simulations, dark matter is more centrally
concentrated, the extent not simply depending on the presence/absence of AGN
feedback. The scatter in global quantities is substantially higher than for
non-radiative runs. Intriguingly, adding radiative physics seems to have washed
away the marked code-based differences present in the entropy profile seen for
non-radiative simulations in Sembolini et al. (2015): radiative physics +
classic SPH can produce entropy cores. Furthermore, the inclusion/absence of
AGN feedback is not the dividing line -as in the case of describing the stellar
content- for whether a code produces an unrealistic temperature inversion and a
falling central entropy profile. However, AGN feedback does strongly affect the
overall stellar distribution, limiting the effect of overcooling and reducing
sensibly the stellar fraction.
