Setup:

i7 2600 + 16Gb

GeForce GTX 970 4Gb

Win 7 64

NVIDIA driver: 10.18.13.5900

Use the game installer recommended settings of ultra and everything maxed.

At 1920x1080 I get 60 FPS indoors, and 35 to 60 outdoors depending on where I am. Closer to the cities and it drops into the 30's and 40's.

These are good to tolerable framerates but there is a severe intermittent stutter that happens at the same points everywhere (but at many many points in the game). For example I have a save right outside the Boston Airport settlement. As I head down the road it occurs every time right as I approach this large puddle, then as I move past that and near a bend in the road it happens again. Every time I'll get a drop from 40-50FPS to < 10 FPS for a second or two. In other places just looking around will cause it. Many times I notice texture/object pop-ins in the distance at the moment this is happening.

Running task manager and Afterburner, I see that when this FPS drop/stutter occurs, CPU and GPU are typically well under-utilized and in fact usually dip during the stutter, CPU may fall from 50% to low 20's. GPU never seems to get above 70% and may drop into the 40's 50's during the stutter. Memory utilization for the game hovers around 2.5Gb with plenty of unallocated mem left.

I've tried all the setting suggestions including v-sync, no v-sync, forcing v-sync in the NVIDIA control panel, borderless, frame limiter (which really made it worse) etc etc... As an extreme test I turned off or minimized every graphic option such as shadows, god rays, LODs, everything that could be minimized or disabled except screen res. Doing this increases my FPS a little, but the same big stutter is still there in all the same places and I could swear it may even be a little worse with graphics turned down if that makes any sense! Perhaps it is because running I get to the sticky points faster with all the options turned off and thus it seems the stutters come more frequent. Nothing seems to have any affect on this.

To be clear this is not "micro-stuttering" where I am stuttering herky jerky 100% of the time, it is perhaps every few to several seconds when I am running full speed ahead down roads, through the wild, or panning around.

Is this just the way it is due to loading cells as you advance through the map? What is the limiting factor/bottleneck for the texture/object loading/pop-ins? It is obviously not CPU or GPU.

I've confirmed this running around with no followers and no FO4 mods (I have CBBE and some outfits). I was also using ENBoost which I turned off. I walk around outdoor with 60 FPS then I see some trees up ahead pop-in and FPS goes to 1-10 momentarily. But it happens very frequently say every 20-50 feet or so in game, sometimes just turning around. I do notice in resource monitor that HD activity increases at these times. I knew defreg probably would do little to nothing, which it didn't. Again, bumping down shadows, fades, etc... does not fix this problem. Is this something where an SDD might help?

Should my expectation be that this game is just choppy like that, specifically outside? I don't want to spend time trying to make something work that never will. Should I assume that as we are moving about outside textures need to load and when they do, it will cause the computer to momentarily freeze while it is doing it?

I don't get the stutter and run game (and whole computer) on an SSD. You could try using a http://www.nexusmods.com/fallout4/mods/102/? that allows you to adjust range of texture pop in (it's a multiplier so I maxed mine so the best texture pops in from far away rather than up close) - you will want to test out what works best for you though. You'll be able to adjust a bunch of other things as well using that linked mod, which might help you.

If you think your HDD is being thrashed you can http://tweaks.com/windows/39199/how-to-detect-what-process-is-thrashing-your-hard-drive/ using perfmon.exe (Resource Monitor) or Process Explorer.

Ok crazy "fix" and I guess something I should have done to begin with. I rebooted. Now 60 FPS everywhere, loaded a bunch of mods and spawned a bunch of NPCs to push it, but still hums along with just tolerable micro second pauses/dips here and there.

My guess is after extended play and restarting the game several times, something gets borked with the NVIDIA card or drivers or OS that needs a reboot to correct.

And thanks for the tips Tawnee! I use perfmon on the job quite a bit and it is a good tool. According to Microsoft, memory and CPU seen in task manager is not as accurate, potentially misleading which is why they push tech folks to use perfmon instead.

np Glad it's self-fixing!

Probably some memory leak.Windows... Anyway it happens to Linux too.