This is not true, at least for my risers. Now I have to get new ones. My risers are 4-pin molex and I tried to use the 6-pin to 4-pin converter (6 pin from PSU, 4 pin on riser). Perhaps it would work if the riser had the 6 pin and you were trying to power from 4 pin, but unfortunately I just found out that my risers use the 5v power. Apparently from what I’ve read, risers with the 6-pin input have 2 regulators to provide their own 5v/3.3v requirements from the 12v, but any that have just the 4 pin molex require the 5v line from the PSU. M goal was to not use up so many ports on the breakout board just to power risers, but alas it has ended up costing me both time and money. Perhaps you can design a breakout board that takes the risers into account a little better?