The OP has a low budget Intel Pentium system. He may just want the lowest price graphics that work with Mojave. Then the number of CUDA cores or ram speed aren't much of a factor in the decision.I have to disagree with the choice of the GT 710 when the GT 1030 is available.
That card is one of the better ones for price/performance in High Sierra. I recommend it in my High Sierra guide for the Dell Optiplex models. Pretty quiet, low power draw, decent performance.But for his information, here is the one I bought:
I don't see any hardware in your profile. Please fill that out first.I had my system running Mojave