I pre-ordered by nMP back in 2013 and had a pretty early delivery. I am completely happy with it. However, since buying it a lot of my work has changed. I was previously doing photographs, PS CC & LR, but now I am spending most of my time working in Premiere Pro with 4K footage. So the configuration I bought was focused on clock speed and not cores. I have the 3.5 Ghz 6 core with 64GB RAM and D500 graphics card. I have seen online that you can buy new CPUs and upgrade. I looked for a graphics card upgrade but could find any thing. Can you up grade the graphics card? Is this going to be worth doing?