Let's say you have EVGA SuperNOVA 850 GM SFX Form Factor and EVGA SuperNOVA 650 GM SFX Form Factor units..Then according to the Which EVGA Modular Cables are compatible with my PSU? EVGA FAQ, yes the cables are not only compatible between each other, but with other units as well.

If in doubt, you can always Contact EVGA or hotwire/jumpstart the PSU and use a Digital Multimeter to check the component-end power and ground pinouts which are widely found on the internet..Component-end pinout is Intel industry-standard while the PSU pinouts are not.