vegetaleb wroteIf you have 2 rails of 18A and 16A on 500W the combined will be?
Like I said. have 2 rails is like having 2 separate power supplies, one being 18A and the other 16A. However some modern power supplies combine those rail and make them work as one big rail, or in this case 18+16 (34A) rail. However if your PSU is not that fancy or modern, the graphics card PCIE power cables come off a single rail.
Moral of the story having 2 rails that are 18A and the other 16A is not enough for a card that needs a 24A rail. Since they're separate rails and don't work with each other.