Is it okay to use a 4pin molex straight from the psu into a powered riser instead of using a sata to molex adapter? I would assume that it would be okay, but I did this for the first time and the card is running extremely hot.
You supposed to use molex. Using a sata to molex cable can be problematic (https://i.imgur.com/xzTr75h.jpg).
The card being hot is natural as it's working (if it's not super high). If your molex or sata cables start to heat up then you have a problem.
I'd recommend only plugging a maximum of two cards per rail even if that rail has 3 or 4 molex or sata connections.
If you use the USB powered rise, that is a good advice. If you use the RX 480, it can draw 75 W each connector.
