  We are commissioning a 2.5-MeV proton beam for the Integrable Optics Test
Accelerator at Fermilab, allowing experiments in the strong space-charge regime
with incoherent betatron tune shifts nearing 0.5. Accurate modelling of
space-charge dynamics is vital for understanding planned experiments. We
compare anticipated emittance growth and beam loss in the bare IOTA
configuration using transverse space-charge models in Xsuite, PyORBIT, and MADX
simulation codes. Our findings reveal agreement within a factor of 2 in core
phase-space density predictions up to 100 synchrotron periods at moderate beam
currents, while tail distributions and beam loss show significant differences.
