Even Silverstone site mixes cables as they state for some second gen that the work for all power supplies build after 2009. They do not work on the 3rd gen which it is build for sure "after 2009". You need to check the list of compatible power supplies on each cable, the list is correct. They do have soft cables silicon based for the 3rd gen, search for the model number you find on Silverstone site , amazon.com has some of them. They are shorter than standard ones be sure they are long enough for your case. This one: https://www.amazon.com/gp/product/B099Z5FTWK/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

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As you see cables do not match even between same manufacturers different gens and Silverstone is better than many other manufacturers which change the cables from one model to the next. You are lucky that the cable did not fit if not you probably would short both the PS and the card.