As cast specimens of eutectic Si alloy refined by Sr and with transition metal dispersoid were subjected to hot torsion in the ranges 300-500 degreesC and 0.1 to 10 s(-1). The flow curves rose very rapidly to peaks at 0.05-0.1 and then declined almost linearly per unit strain by about 20% at the highest stress (similar to200 MPa) and 5% at the lowest (similar to30 MPa). The ductility over these extreme conditions ranged from true strains epsilon(f) similar to0.6 to 4.5. The dependence of flow stress on strain rate E and temperature T were fitted to power, exponential and sinh laws along with an Arrhenius term with activation energy 152 kJ/mol. Optical microscopic examination exhibited fairly uniform distribution of fine eutectic constituent in a primary Al solute matrix with occasional fine primary Si particles. As the total strain epsilon(f) increased there was increasing evidence of elongated regions of primary Al phase and of some aligned primary Si. At high epsilon, the surface became roughened with fissures and internal cracks are associated with bands of primary Si particles. The behavior is compared with other Al alloys notably A356 alloy. Although the transition metal dispersoid particles improve the creep and wear resistance in automotive service, they do not markedly reduce the forgeability.