Aluminum silicon carbide Metal Matrix Composites (Al-MMC) are widely used in aeronautical and automobile industries due to their excellent mechanical and physical properties. However the harder reinforcement particles make machining difficult. Tool wear occurs more quickly and reduces the life of the tool. This paper presents the experimental investigation on turning A356 matrix metal reinforced with 20 % by weight of Silicon carbide (SiC) particles, fabricated in house by stir casting. Fabricated samples were turned on medium duty lathe with Poly crystalline Diamond (PCD) inserts of 1300 and 1500 grade exposed to various cutting conditions. Parameters such as power consumed by main spindle, machined surface roughness and tool wear are studied. Scanning Electron Microscope (SEM) images support the result. It is evident that, surface finish, and power consumed are good for 1500 grade when compared with 1300 grade at higher cutting speed and tool wear is strongly dependent on the abrasive hard reinforcement particles.