You all are overestimating the performance impact of Godrays. Ultra is a lot, yes, and high is better, true.
The most performance impactful setting by a mile is Shadow Distance. The longer your shadow distance the more draw calls issued, exponentially. Ultra = 13000 distance, High = 7000, Medium = 3000 and I don't know what low is. I can comfortably run "High" e.g. 7000 on my rig below at 1080p (drop into the 50s very rarely, otherwise capped at 60). This will depend mostly on how fast your CPU and RAM is. My 290 is about on par with your 970 (2x290 still doesnt work in Fallout)
Change shadow distance to medium and godrays to high or lower and your performance problems will clean right up.
The 290 is faster than the GTX 970 in Fallout 4, and does better as resolution increases.
Not trying to turn this into an OP should have gotten an R9 390/290, but the GTX 970 is not on par with the R9 290 in this game. Launch? Of course AMD is bad in a gameworks game. Later when no one is paying attention? Great.
Really the GTX 970 is a tier behind the R9 290 in this game (and a lot of new releases it feels like).
I think 1440p is manageable with the right settings on the R9 290.
On the GTX 970, I think you're better off going after 1080p.
I can't speak to GTX 970s with good OCs though.
Edit: The GTX 970 is literally a tier behind the R9 290 at the OPs chosen resolution of 1440p as it matches an R9 280x. So given the fact OP is playing Fallout 4 why should he be impressed with his GTX 970? It's literally slightly faster than the HD7950 I just had. It's just as fast as an HD7970, an EXTREMELY old level of performance at 1440p. It's far slower than the R9 290 at 1440p. All while being newer, and more expensive than all of those cards right now.
So yes, OP should feel unimpressed given the game he's playing and the resolution.
Edit2:
Latest game only makes it feel worse so I'd feel pretty annoyed and I really don't think it'll get better when Pascal arrives, especially with the GTX 970s memory configuration.