So, the new proposed rig is going to run AMD. You're already running a 3930k as a cruncher, but it's too much of an effort to figure out what is going on with an Intel system. Seems like an odd ask, but there's a way to summarize all of this.
http://cpuboss.com/cpus/Intel-Core-i5-4690K-vs-AMD-FX-9590
If you scroll down, you'll see a couple of different ratings. The two of particular note are the per core performance (gaming is still largely that), and the overall performance per watt. As you're looking at these numbers, we've got two conclusions. The AMD chip is only worth while in intensive loading (ie, lower initial cost is repaid with higher operational costs). On the single core performance the Intel offering stomps all over the AMD offering. This is comparing a 4 core to an "8" core processor, and their performances are still the same. That, in numbers, is why people are telling you that buying new AMD hardware now, that you actually have to buy in installments due to the budget, is not a sound choice.
Why I'm comparing the 9590 to the 4690k should be noted. Both are DDR3, so they can be a system upgrade and not a new one entirely. Both are on a functionally dead socket. Most importantly, both of these offerings are at about the same price point now.
So, let's just assume that you're staunch anti-Intel enough to stick to your guns. First off, your dedication is both admirable and insane in equal measures. You have shown Intel that you can give them up, but it's getting a functionally worse piece of hardware. The best up-side to AMD is that because they're less power savings oriented their chips generally overclock well. If that's your thing, then I suggest some patience. You cite that nothing is wrong now, but follow that with a declaration that you are going to upgrade for kicks over the next few months. Can you wait a little longer?
It's already been said, but AMD is promising a lot with Zen. Within striking distance of Intel style promises (DDR4, only 1 or two nodes behind Intel, and ditching the bastardized core designs of Bulldozer). I myself am going to be looking at them for my next upgrade. I'm tired of the Intel BS, but a 40-50% drop in performance per watt is just insane. I'll pay the extra few dollars up front, because that kind of power draw difference (even with the cheap electric prices in the US) pays for itself and then some. Zen could potentially change that, and saving up money for a year will mean instead of parting a machine together you can get something nice all in one shot whenever AMD actually rolls Zen out.
