Just tested the Thermal Protect Cable from Corsair and compared it with two other 12v-2×6 cables that comes with PSU one is a native 12v-2×6 and one is a pig tail with 2 pcie connectors on the PSU end.
I have also included the thermal imaging in the video.
Temperature wise all 3 of them were sitting around 40-45°C on the GPU side and about 30-33°C on the PSU side.
But the Cable Comb on the Thermal Protect Cable(the comb with corsair logo on it) holds the pins very tightly and keeps it stable which is very good.
I have made a full video and below is the link to it if you are interested.