Remember the GeForce4 MX? The low-end GPU was pretty forgettable, to be honest, but Nvidia is bringing back the MX moniker for handful of new mobile GPUs. Instead of being budget offerings, these new parts start at the high end of the mobile GeForce lineup. The fastest of the three is the GeForce GTX 680MX, which is the first mobile GPU to offer Kepler’s full payload of 1536 shader ALUs. The previous top-of-the-line model, the GTX 680M, has only 1344 ALUs.
Nvidia bolsters mobile GPU lineup with MX models – The Tech Report