Fast and accurate large-eddy simulation (LES) of the atmospheric boundary layer plays a crucial role in advancing wind energy research. Long-duration wind farm studies at turbine-resolving scales have become increasingly important to understand the intricate interactions between large wind farms and the atmospheric boundary layer. However, the prohibitive computational cost of these turbulence- and turbine- resolving simulations has precluded such modeling to be exercised on a regular basis. To that end, we implement and validate the Generalized Actuator Disk (GAD) model in the computationally efficient, graphics processing unit (GPU)-resident, LES model FastEddy ^®. We perform single-turbine simulations under three atmospheric stabilities (neutral, unstable and stable) and compare them against observations from the Scaled Wind Farm Technology (SWiFT) facility and other LES codes from the recent turbine wake model benchmark of Doubrawa et al. (2020). Our idealized LES results agree well with observed wake velocity deficit and downstream recovery across stability regimes. Turbine response in terms of rotational speed, generated power, torque, and thrust coefficient, are well predicted across stability regimes and are consistent with the LES results from the benchmark. The FastEddy ^® simulations are found to be at least two orders of magnitude more efficient than the traditional CPU-based LES models, opening the door for realistic LES simulations of full wind plants as a viable standard practice.