A high-order discontinuous Galerkin method is applied to the compressible Taylor-Green vortex at Mach 0.1 to evaluate the method, and to investigate alternative means of evaluating solution accuracy when an exact solution is not available. Two distinct variants of the viscous terms produced nearly identical results, which is consistent with the convection dominant nature of the flow. Grid refinements on hexahedral grids were performed to an effective grid resolution of 1042 3 degrees of freedom. Error analysis using norms of the change in the solution between grid refinements indicate that the solution is entering an asymptotic regime at an effective grid resolution of ≈369 3 degrees of freedom. Simulations on tetrahedral grids produced similar or better results, in particular, converging to peak enstrophy on much coarser grids. These well-resolved results indicate that the compressible solution is measurably different from the incompressible case, and that the incompressible case cannot be used to quantitatively evaluate the accuracy of a high-order method. Further, a volume-averaged quantity hides much of the details of the flow and is not a suitable metric for evaluating a high-order method. Norms based on direct comparison of a sampling of field values between successive grids provides a reliable measure of error convergence.