Bethesda, why are some people experiencing fps drops while some are not? hardware combos? any speculation on this? Running a gtx 970ftw+ i7 4790k. Also tested with a 3770, both combos seem to experience the same issue.

Could be a multitude of reasons:

1) Different OSs and

2) Different Driver Combos, sub par drivers, buggy drivers;

3) Different windows settings, different services combinations, etc.;

4) Overclocks, user or factory set, causing issues with the game;

5) The conversion to the engine being 64 bit exclusively had some unexpected side effects I'd recon.

I just don't get why fps drops only occur in certain areas while most areas remain stable.

I myself did have some performance issues, but I think that had more to do with my GPU being maxed out and thus was causing stutter, so I had to limit my FPS to 30 to prevent it from being maxed out. That and my CPU is just above minimum spec, and I would imagine that lack of hyperthreading on my CPU plays into it.

Aside from the aforementioned issues, my Fallout 4 experience has been smooth, smoother and more stable than Skyrim was at launch, and my PC is about as optimized as can be for gaming. I only have what is necessary for my system to function running, and have any extraneous services turned off or anything unnecessary uninstalled.

Well, some areas are more densly packed than others (Whether they are with or without NPCs), such as Corvega Factory, so there is a lot more to render I'd imagine. Shadow distance is also horrible in this game, the jump from medium to high shadow distance is 3000 to 14000, and from high to ultra it is 14000 to 20000. I have shadow distance set to medium for this reason.

Even on medium fps drops. Doesn't make sense with my specs.

True, not denying that people are having FPS issues, but I'd say that those people are in the minority. My experience from being on the forums since before Skyrim was released, and from working in customer service (To be clear, not Bethesda), is that only those having issues tend to come to to forums to report issues, people not having issues aren't going to register just to say everything is fine, so those having problems are overrepresented in the forum population right now.

I'd imagine Bethesda is collecting as much information from the people having issues as possible and will try to find a fix that works for most everyone.