My rig has 9*RX570 which runs on two Antec HCG 1000 PSU. One PSU which powers the MB through a dual PSU power cable spilliter has 4 GPUs and the other one has 5 GPUs.

The PSU which has 5 GPUs is very hot compared to the main PSU (4 GPU + MB). My city temperature is 30-40C. Do you think it could be due to PSU spilliter cable? I am thinking of ordering Add2PSU and replace the spilliter cable. Btw my GPUs are undervolted and bios modded.