Texture rendering/graphics issue on PC

OK, first, running off your specs is less helpful than posting a dxdiag (as it tells us everything, not just the bits you think is relevant.)
Secondly... Could you post one or two screenshots HERE (preferably not sideways ones) and point out within those screenshots where the problem bits are? As those 'twist your head this way then that' screenshots you posted just looked like a bunch of pictures of boring walls to me. Or perhaps you could post a picture of what you think it is supposed to look like to compare to what you've got. 
Upgrading to Windows 10 is just as likely to cause problems as fix them (the game was made for Windows 7/8). 
Using an Nvidia card, GeForce experience should tell you what it believes are optimal settings for your game (saying that, I turn my graphics up higher than it says, mostly due to mods making that a necessity 😛 ). 

You should also be aware that there are some mods out there that improve textures etc. It's possible the videos you watched were using one of these, hence the improved graphics. If you want help/information on modding, the best place to go is probably here, as that is where the tools were made. 

(Just found this, if you go to the images tab and compare the 'before' pictures to the 'after' pictures, is that the sort of difference you were noticing? If so, think we found your 'problem').

Hey, thanks for the reply.

I have no idea what happened to the screenshots I've posted, I definitely didn't mean them to be that way lol. Sorry about that. I edited the opening post a bit.

I attach the one that really shows what the matter seems to be. A "boring wall" is exactly what you should see, but also a boring wall that is rendered in a quality that is definitely not highest graphics Dragon Age Inquisition. It is definitely not a mod that I'm missing, and it's not that the textures aren't high resolution, they just look completely wrong. Here's a video from the very same wall I have my shot of, behind Cassandra:

https://www.youtube.com/watch?v=E-ct9YDBoHw

THAT is how it looks by default, and it should be that way in the interiors, the fortress in Hinterlands, etc. What I have is a really bad looking mess for no reason I'm aware of. I also attach a shot of the armory nearby just in case.

I'll do a dxdiag once I updated my BIOS, that's the last I can think of but I honestly don't see if that could be it. Thanks for the hint anyway.

OK, I think I see what you mean now (those other screenshots were too hard to look at). In front of your character, a sort of... square of different wall? 
Mine sometimes does that when I first enter an area (mainly in Skyhold, with all the people and junk to load), but it 'fixes' (there's a better way to put it... my brain just won't tell me) itself bit by bit after a few seconds, I'm guessing yours isn't doing that? Have you ever fallen through the floor in Skyhold? Often happens running from the main hall into Solas' area when you don't give the game enough time to load everything. 

I think the dxdiag will help, might want to include what game graphics settings you're using, too. 

Yes. That seemed to be the issue; in patches the wall looks made of a completely different texture than the majority of the stuff. However, someone on reddit just linked me a gameplay video in which someone else playing on absolute ultra graphics has the same thing going on. It might not be a glitch after all, but then again it's the very first time I've seen it look like that outside my game, and I'm still puzzled at why it is actually so. I still think it looks godawful, but at least I know now it's not only with my game so I can stop worrying about hardware issues.