You write you use this system for all your video work and then ask for "minimum requirement to perform this work."
It looks like you already are there!
I have Dell Optiplex 780 system with 4GB DDR3 ram, 500GB SATA HDD. I want to use this system for my all video editing work. What other hardware should I add in to make it work smoothly for all my video editing and animation work? Usually I do not have to grab videos from any camera or player. My clients upload all the videos for me to download and start work.
Please suggest minimum requirement to perform this work. Note: I will use Adobe After Effects for animation and Adobe Premier, both CS5.Thank you