Since you probably know exactly what he does with it, and you can justify taking out the GPU for the 940 and the 790GX, I would probably agree with you Joga. And the 790GX will be enough for him I think, it's not as if he's even going to be doing 4-way CF.
If you spend the extra 100 you will have a computer that lasts longer and is faster. Video editing is multi-threaded so a dual-core would not really be sufficient. However a quad-core is overkill for gaming...so far. If you have a quad and a dual that run at the same clocks they would perform equally while gaming.