Vertical resolution is an often overlooked parameter in simulations of convection. We explore the sensitivity of simulated deep convection to vertical resolution in the System for Atmospheric Modeling (SAM) convection resolving model. We analyze simulations run in tropical radiative convective equilibrium with 32, 64, 128, and 256 vertical levels in a small (100 km) and large domain (1500 km). At high vertical resolution, the relative humidity and anvil cloud fraction are reduced, which is linked to a reduction in both fractional and volumetric detrainment. This increases total atmospheric radiative cooling at high resolution, which leads to enhanced surface fluxes and precipitation, despite reduced column water vapor. In large domains, convective aggregation begins by simulation day 25 for simulations with 64 and 128 levels, while onset is delayed until simulation day 75 for the simulation with 32 vertical levels. Budget analyses reveal that mechanisms involved in the generation and maintenance of convective aggregation for the 32-level simulation differ from those for the 64- and 128-level simulations. Weaker cold pools in the 32-level simulation allow the boundary layer in dry regions to become extremely dry, which leads to an aggregated state with very strong spatial gradients in column-integrated moist static energy. Understanding both the triggering and maintenance of convective aggregation and its simulated sensitivity to model formulation is a necessary component of atmospheric modeling. We show that vertical resolution has a strong impact on the mean state and convective behavior in both small and large domains.