MSI introduced the GT60 and GT70 notebooks in March, and the latter has already received an upgrade to NVIDIA's GeForce GTX 675M GPU. Now both laptops are taking another step up, this time to the GeForce GTX 680M, NVIDIA's latest GPU, with 4GB of dedicated memory. The refreshed 16-inch GT60 and 17-inch GT70 are available in the US today for $1,899 an