I'm not sure about all the technical stuff, I will just write about my experience.
I saw a lot of the crashes. Most of the times I wasn't getting a BSOD a lot, but it would freeze for a second and then unfreeze again when lucky. Otherwise I would need to hard reset my pc, or sometimes, but rather rarely get a BSOD.
What I noticed regarding drivers, and I tried all between 314 and the latest beta. The 314 runs more stable for me. The latest beta gave me LOT more crashes and more frequent BSODs.
Then I tried the TdrDelay "fix" which is proposed in many youtube videos. This didn't help. Neither it helped to set all FFXIV settings to the lowest possible value. Eventually I checked my temperatures and my GPU was around 80 degrees most of the time. This didn't seem to be a big problem though and I didn't really notice a big correlation between crashes and temperature spikes. I also set my nvidia settings to "performance always" or something like this, which also didn't help, although I had the idea that crashes were less frequent after all of this together with the 314 drivers.
As I am playing on my Dell laptop, holding a nvidia 540m with optimus technology, I wasn't able to do a lot in the bios. What "solved" the problem for me, was to download some nvidia system config tool and underclock my GPU to 630mhz. Since then I haven't had a single crash, apart from the moments where it would unload the profile and return to the normal 672mhz. So at least for me, there seems to be a problem with the general way my GPU works. A lot of people have pointed out that this kind of stuff happens when your GPU doesn't get enough power. This kind of makes sense as you would figure that it makes a system run unstable if it has a too low voltage. So since I couldn't crank up the voltage, I just underclocked my GPU.
I'm not saying this is the fix, or the way to go, I just hope that it helps some desperate soul to get to play in a normal way.
