I'm currently running on a 2.66 GHz Intel Core 2 Duo with a NVIDIA GeForce 9400 256 mb - I do a lot of video editing and really need to upgrade as my computers performance (lot of lag, ridiculous export times, and difficulty using external monitors) is significantly annoying. What are my best options for processor and graphics card upgrades? (I have already maxed out my RAM upgrades) Aiming between most cost effective and performance efficiency is best. Thanks!!!!