i was wondering which one to get, because i am trying to save a little $ since the sale price is about a 7950 price. also i believe the evga 670 has a reference 680 pcb, not sure about the 7970, it is important that it is reference so i can watercool.
i know the psu is a little overkill but im going to upgrade soon after
if i can i am trying to get the price down to or less than $1500.
also if i buy from a vender like ncix, newegg, amazon, or frys, if a couple parts like the aftermarket heatsink doesn't fit with the ram, can i just return it and buy a different one?
A lot of it is a question of degree. i7 gains you virtually nothing, over i5, in terms of gaming. If using photo/video software, that uses hyperthreading, like Adobe, then i7 gives a decent performance boost. You do have to be doing a fair bit, though, to justify the extra cost.
If you are using Adobe software, then certainly get nVidia GPU, as they are better utilised. With some other software, like Sony Vegas, I don't believe there is any such advantage, and it may even favour Radeon.
When you speak regarding PSU size, of upgrading, if you are talking about adding 2nd GPU, 750w would be more than adequate. Whilst not FULLY modular, the Rosewill Capstone is a good, lower cost option.
I am in UK, so not sure about returns policy, in USA, but, if you use low profile RAM (1600 MHz Cas9 DDR3), like Corsair CML, Crucial Ballistic Sport, or GSKill Ares, you won't have an issue.