The onset of neoclassical tearing modes (NTMs) is regarded as the most severe limitation to the maximum achievable normalised plasma pressure bN(bN = btaBt/Ip, bt = 2m0 < p > /B2t, Bt: toroidal magnetic field , < p >: averaged plasma pressure) in tokamaks. According to a simple analytical description using the generalised Rutherford equation, the saturated width wsat of these islands is expected to grow proportional to the plasma pressure. Although, taking into account non-linear effects, a saturation of this behaviour is expected for very large pressures, wsat should always grow with increasing plasma pressure. On ASDEX Upgrade however, a regime with high confinement at high bN values has been found although (3,2) NTMs are present. In this regime the amplitude of the NTM does not grow smoothly.