Iirc, he's also on a 970. People with far more powerful systems still get inconsistent performance, so yes, this is the game's fault (or more precisely: that of that abysmal engine).
Hmm. Well maybe if I were to record/stream it it'd begin to slow down, but like I said, as of yet not seen any of what he was showing or what you've described.
Also about the engine; Skyrim always has run fine and this tweaked version doesn't seem to be much different, they just updated it to use PBR instead of older rendering methods, like most games do now - But with all that Skyrim money I'd assume they'd do a little more than just tweak it a little.
But from the sounds of it, it has been undercooked as a package. But as a whole I think I can say I am satisfied with the game I've got to play so far, vast and fun.
PS: Who is Lirc? - Some big Youtuber/Twitcher? I only really watch Robbaz.
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970 here - frames going wildly from 25 when scoped, 40-45 in cities and sometimes in weirdly empty areas, otherwise 50-60. Game is not optimized well - which is weird cause Gamebryo runs on any toaster usually - maybe it's all the fancy lighting they added and forgot to change bits and pieces of their code.
Hmm. I'll put up a counter next time I play - But I have definitely not dropped low enough for it to be noticeable.
Yeah the optimisation could have been much better, bit shoddy as they could've improved textures if they didn't have all these issues with the console versions.
PBR is normally a better system, it's less heavy on the calculations and in most cases is just better than older rendering methods, the new lighting shouldn't be the blame.