I noticed my Catzilla score dropped a LOT on a card I had, right after Catzilla "updated". I wonder if benchmark developers set the bar higher as hardware improves. That was the only thing I could think of to explain the dramatic drop.
Have you repeated the test, watching it from the start to the end? Glitching out during one part (power shortage/overload/overheating => freeze or throttle) could affect the average score quite significantly. Not sure about 2017 but some years back unclean driver reinstalls could do silly unpredictable things like slower performance with no obvious glitching, so you wouldn't even know something was wrong if you didn't know how fast the relevant card was supposed to perform. Or perhaps something's overriding DirectX version selection or you have some quality enhancements enabled in drivers and overriding the benchmark's own settings? I'd grab some other tests to see, perhaps switch all driver settings to controlled by application.
Yea I realized last night after I made this post I was running Time Spy which was the DX 12 version of the bench and for older GPU's / laptops I should run Sky Dive, and back then when I got the score of 6.9k with 3D Mark 11, no telling which test I was running then.