Run YOUR game, but lower your resolution and eye candy.
If your FPS increases, it indicates that your cpu is strong enough to drive a better graphics configuration.
If your FPS stays the same, you are likely more cpu limited.
The cpu performance of your FX-8350 may be the primary limitation.
What is your motherboard? Is it cf capable?
If you do decide on a graphics upgrade, buy a single strong card.
CF will win you synthetic fps benchmarks.
But, your gameplay experience is likely to be better.
Dual gpu, particularly with low end cards is prone to stuttering and screen tearing.
More games are not supporting dual gpu(I don't know about ark)
I suspect you would be much happier with a GTX1060.