The density transformation of upper layer North Atlantic water by surface heat and salt fluxes plays a key role in the Atlantic Meridional Overturning Circulation (AMOC). This water mass transformation also depends on the surface ocean state and thus it presents a potential mechanism through which model temperature and salinity biases can reduce or enhance AMOC. In this study, we compare surface water mass transformation between two forced, 20th century ocean-sea ice simulations using the Model for Prediction Across Scales ocean and sea ice codes of the DOE Energy Exascale Earth System Model (E3SM). One simulation uses a high resolution, eddy-permitting configuration and produces an 18 Sv mean AMOC at 26.5 N, the other uses a low resolution, eddy-parameterized configuration and produces a weaker, 9 Sv mean AMOC at the same latitude. Surface water mass transformation is an area-integrated quantity that we compute over two regions: (1) the Irminger and Iceland Basins where Subpolar Mode Waters form, and (2) the Nordic Seas where Atlantic and Arctic sources combine to form dense Overflow Waters that flow southward across the Greenland-Scotland Ridge. To better characterize the circulation associated with these regions, we also compute the net transport through the Irminger and Iceland Basins boundaries, specifically along: (1) the Overturning in the Subpolar North Atlantic Program (OSNAP) East line, and (2) the Greenland-Scotland Ridge. We find that surface transformation in both regions increases at high resolution and decreases at low resolution as the simulations progress. The surface transformation decrease at low resolution is consistent with the development of a surface cold, fresh bias in the western subpolar gyre, and is preceded by a freshening of both the upper and lower layer transports across OSNAP East within the first year of the simulation. We attribute this freshening of transports to circulation biases in the subpolar gyre that also appear early in the low resolution simulation. This link between early circulation biases and water mass transformation provides new insight into the weak AMOC at low resolution.