I have a HTPC as my main with a good graphic card but I have the same problem as SpeakinSilence.

I am using an AMD A8-5600K APU

Graphic card is Radeon R7 260

64bit Windows 7

I run two 250 gig SSDs one for the OS the other for games

But I only have 4 Gig of ram, I think this maybe my problem?

I also have no problem running games like Witcher 3 on higher setting then I use in Fallout 4.

I have all the settings as low as they can be as well as all tick boxes un-ticked.

I use Fraps to get my FPS, and it well start off at 50-60 but it does not take long for it to drop away, in 10-15 min it can be unplayable to the point where I have to Alt Tab and force Quit within say 30 min of play.

I get back in and ariound the same time later I have to force quit again.

If there is a way to remove all shadows I could see if that fixes my problem, I say this as it seams to be better after night fall.

PS: I cannot get Cut and Paste to work at all via Notepad.

requirements are there for a reason and 4 GB does not cut it. you think they just lied so you would waste your money buying more system ram?