Just been comparing these two and wondered if anyone could explain the results: Pixel Shaders - the higher the number the better? The range of the core speed for the 555m starts lower and goes only slightly higher than the 550m - which is better? Same as 2 but this time for Shader Speed - again, which is better? Max memory speed is the same for both? Are there any advantages for being able to go lower? Do you want a higher memory bus if possible (so is the 555m better here)? 3DMark appears to be a program used for testing the cards performace, with 01 being the oldest version, 06 the newest. Why does the 550m have higher readings than the 555m on the older version but not on the newer? Again with the 3DMark, what do the red/pink and green bits mean?