And those cables are for sure the original ones that came with the PSU?
Most cables from modular PSUs are not compatible to others, because there is no standard for this on the PSU-side.
Corsair for example has afaik 3 or 4 different cable types/generations for their modular PSUs and you absolutely should not mix them (even if they physically would fit), because of different pinouts.
If you use a cable that is not compatible with this particular PSU, chances that you blow up your components are very high.