I suggest getting MSI Afterburner, it's an Overclocking utility, but not only that, it allows you to monitor your GPU temps, GPU usage, and fan speed. While running FFXIV and doing something intensive (go somewhere that has a lot of foliage or players), check the temps. Don't worry about the fan. The only time you should be worried about your fan speed is if your fan speed is at 100% but your temps continue to climb for several minutes. That's usually a sign that you need to clean your computer out and/or swap out the thermal grease on your GPU for a new grease (requires a little bit of taking apart).

You could use that utility and post what you see as your average temps if you're concerned, but I wouldn't worry too much about it as you just said you made a new build.