@Paget89 I did similar mod last year but noticed that the sata expansion board I had caused issues with C states. System was stuck at C3 causing heat and power.
In my case I was using the boards 12v & 5v power for 2 3.5” HDD’s. No extra psu needed. I’ve seen people use 4 HDD’s without external power.
In my current scenario, I am using the inbuilt SATA connector for one main HDD and a USB sata for backup HDD. No C state issue. Goes to C7 state. Of course power to HDD’s come from main board.
