I have not had word from a GM, since the last post I responded to.

Anyway. On Sunday (I been feeling pretty unwell as of late) I am going to attempt some fixes, I am not sure if it will be the right way. But it's the best I can do to my knowledge.

There are some things to me which stick out like a sore thumb about my problem.

* I've tried playing FFXIV on a diffrent GPU (GTX 960) even on the lowest possible graphics setting which did not change a thing.
* Reinstalling/starting afresh with Windows 10
*Reinstalling (Not rolling back because of unavailability of the option) 391.35 that used to work now doesn't

These to me, kind of point to either a motherboard fault or something in the software which is bugging things out.

The motherboard theory

My Mobo: Fatal1ty X370 Professional Gaming

The motherboard theory seems to lie at 40% in my mind. As there have been a couple of red flags. like the PC randomly disconnecting components like the Keyboard and mouse. I've even had a big problem where something would prevent my keyboard from connecting to the PC as the disconnection sound would keep playing over and over (with the LEDs on my Razer Blackwidow Chroma, flashing non-stop) till I switch it to another USB port. With the mouse, It does the sound with the LED lights going out and then coming back on again.

I also have 2 Ethernet Ports, the one I was using to connect online. When booting up the machine from cold one day, the port just went dead and refused to work. So I had to switch to the other one (the normal Intel one, the black one).

What I shall try to do as my first fix, will be seeing the GPU works in the other port, since I have not tried that before. If FFXIV's FPS somehow stabilizes without the use of Riva Tuner Statistics Server as the crutch to bring down the fps manually, It will be a motherboard problem and shall try replacing it, that's if it's still under warranty.

Software glitch theory

Now this one stands more at 60%

When looking back to last year, when Windows 10 let me roll back to 391.35. The problems of the FPS errors seem to go away, until I decided to update the GPU's firmware again. So Mainly nothing was wrong with ports.
It also came to my mind that this issue with FFXIV's FPS still lingered after a complete Windows 10 re-installation (I even tried different GPU's post re-installation). So I believe that even though memory has been wiped, there are still broken files lingering around. So this is what I am going to do on the software side if problems are still the same when I put my GPU in another port. (I feel that this is what I did in the old days if things kept failing to work)

First like the people on the Nvidia forum said for me to do, I will update the Motherboard's BIOS to the latest version, so there will be some stability. (then again since this step is kind of risky, I might leave it out)
I shall uninstall FFXIV, then lock myself into Safe Mode, use DDU to uninstall the GPU drivers, then restart.
Then use something like Ccleaner to scan and delete any bugged registry files and any other files left behind - this I believe will unclog the PC of nasty things that might be getting in the way of my GPU's drivers working properly, even when installing older drivers.
After a good reset, I shall install the latest GPU drivers, then reinstall FFXIV and see how it goes from there.

if that doesn't work, I really do not have a clue what to do next...