This should be final update till you get back on, and I do apologize for all the recent additions but it just kept coming back to back.
Short answer:
Game has same problem.
Long answer:
After finishing that v2 run, hoped out of my FC group to run it again. During the 20 minute queue, the lag appears in Ralgahr's reach, one of the high pop places from update that has lagged me at times (not Eureka did not lag but was only there for an hour and it is still rather dead since update). At the time, I had Discord and Spotify open. Got task manager open, while game was lagging, shut down Discord. Lag nearly instantly went away. Kept running around, switching to and from the large amounts of people kinda like I was stress testing. Lag appears again, closed Spotify, lag disappeared right away once again. (At this point, it is in clean boot since those were only programs I turned back on when the game was not lagging in Eureka). This time it took the longest to happen, but it did start lagging once again with everything closed. I opened up my temperature monitoring programs and pushed for lag again. No change in temperature whatsoever between when I was not lagging and when I was lagging.
The only program I know that starts up without the task manager start up is my Overclock, which I of course ensured to shut down prior to testing. So, unless I have some random program I have no idea about, the only programs running at the time of the final lag test was ff14 and just Windows. The only things in the carrot icon menu near the time is NVIDIA settings and Steam as I run Steam version.
The only noticeable thing I have seen, and mentioned before, is that, when I lag, my GPU drops from what is now 60% usage with everything closed to 20%. CPU appears to remain unaffected and at most drops 10% during this time.
With that said, I should now mention:
The game currently is now installed on the C: drive with Windows. Clean boot was done as stated and the few programs I did have were end task'd through task manager. The game is fresh installed and patched, the only thing kept from the previous files is the Documents file for my settings. Of note, this has been done each time, and thus, if something could be problematic in this file, I have mentioned this.
Something of note:
Someone in my FC told me today that many players were having problems with the game maxing out usages and SE was taking down people computer details such as GPU type to try and fix this. While that was interesting, my usages do not seem to be doing that but I though I would mention it anyways.
Final Comment:
There are only 3 things I can possibly think of right now. 1) something is making my GPU quit working in high population areas, thus the drop of usage and lag (1070 and without the Overclock it is untouched since I got it). One thing I just though of that might be of note, my screen has went crazy colors, seizure like lighting, 2 times in the last 3 months, and not recently, but this happened after a power outage were my backup battery failed to stay on. That said, if I recall correctly, this problem did exist before that happened. 2) Kinda related to 1, one of my computer parts is not working properly and FF14 is the only game that brings this problem to light. 3) My internet is too slow, and when the server has high stress areas (high population of players, like exactly where I lag), my internet fails to keep up. This problem has happened on 2, possibly 3, different Internets and the previous ones were very solid.
I find all 3 of these guesses very poor answers, as my notes after each one kinda state. Because of this, I am also going to go ahead and make a forum in a more computer technical focused forum as well but I will be sure to keep looking at both. This problem is very unfortunate and it seems to be getting progressively worse (yesterday was the first time I lagged in a 24 man raid, were I also had one of the bosses not load like v2, though that was while I was lagging, and my internet went completely out for a bit thus I left it as that was the reason because my internet was in the process of dying)
Thank you for your time as always, it has been much appreciated and I do apologize for this ginormous response with another 2 before this. I find it best to give as much information as I possibly can in hopes of finding an answer. Once again, thank you very much for all your time.