#cpsupport GPU and PSU question

A year ago I ordered a prebuilt, a CyberPowerPC - Gamer Supreme Gaming Desktop - Intel Core i9-13900KF - 64GB Memory - NVIDIA GeForce RTX 4070 Ti 12GB - 2TB SSD - Black. I just came home with a 5080, and attempted to put it in, but noticed that the 5080 has 3 8pin connectors, while the 4070ti extended to only three. Does this power supply have a third cable I can plug into? I dug around the nest of wires and did find another 8 pin connector, but if I were to plug the 5080 in, it looks like it would just go around in a loop. Anyways, wondering if that's the one to plug into as I didn't see any others. or is this PSU just not compatible? All i know about the PSU is that its a 1000w apevia.