This study investigates the origin and features of the low-frequency AMOC variability from several ocean simulations, including a large (50-member) ensemble of global, eddy-permitting (1/4o) ocean/sea-ice hindcasts. After an initial stochastic perturbation, each member is driven by the same realistic atmospheric forcing over 1960-2015. The magnitude, spatio-temporal scales and patterns of the atmospherically-forced and intrinsic/chaotic interannual AMOC variability are then characterized from the ensemble mean and ensemble spread, respectively. The analysis of the ensemble-mean variability shows that the AMOC fluctuations north of 40N are largely driven by the atmospheric variability, which forces meridionnally-coherent fluctuations reaching decadal timescales. The amplitude of the intrinsic interannual AMOC variability never exceeds the atmospherically-forced contribution in the Atlantic basin, but it reaches up to 100% of the latter at 35S, and 60% in the northern mid-latitudes. The intrinsic AMOC variability exhibits a large-scale meridional coherence, especially south of 25N. An EOF analysis over the basin shows two large-scale leading modes explaining 60% of the interannual intrinsic variability. The first mode is likely excited by intrinsic processes at the southern end of the basin and affects latitudes up to 40N; the second mode is mostly restricted to, and excited within, the northern mid-latitudes. These intrinsic/chaotic variability features (intensity, patterns, random phase) are barely sensitive to the atmospheric evolution, and strongly resemble the ``pure intrinsic'' interannual AMOC variability that emerges under repeated seasonal-cycle forcing. These results raise questions about the attribution of observed and simulated AMOC signals, and about the possible impact of intrinsic signals on the atmosphere.