Thanks Dave. I noticed that the 390X, Fury X and the 980 all seem to be fairly close performance wise. Where the 980 Ti seems to perform just as good as the dual gpu Titian. Noticing that the Fury X is only maybe 5% better performance then the 390X, I can't see how $150+ more justifies such a small performance gain.
And yeah, I am running a Corsair H100 280mm water cooler. It's been doing a fantastic job keeping this old I7 930 comfortable. Since I have the cooler master HAF-X case, I do have space to mount 2 more small 120mm water coolers if needed. One on the back wall and one near the middle, side of the hdd bay. Just below the video cards. So water cooling won't be a big issue.
Now you gave me something else to think about. A pair of the R9 380X for around the cost of just one R9 390X? I know that radeon cards usually see a very noticeable performance gain when crossfired. But how do a pair of 380X stack up to a single 390X?