Bear in mind Photoshop CC certainly uses different features and stresses your GPU differently than any other software. The realm of graphics software is incredibly complex.
"Game Ready" means very little in the realm of professional tool operation. In fact the features games need are almost certainly not the same things Photoshop needs. I develop graphics software myself, so I have some insights into display driver implementation.
Nor does "WHQL" carry much weight. Ask yourself: How much in general does Microsoft appear to care about quality?
Display driver development is driven first and foremost by people spending money on toys, and it's a very cutthroat business with major players trying to one-up each other constantly. We're kind of lucky "gamer" GPUs can be used with Photoshop at all. There have always been driver releases that are better or worse.
-Noel
P.S., Traditionally I've had about 50% more trouble with nVidia drivers than ATI drivers. And about 300% more trouble with Intel drivers than nVidia drivers.