Do these allow current to flow back to the motherboard? That's an issue I've seen with a ton of these risers, which is easily resolved by modifying the ribbon. With these, I would not be able to make that modification if necessary. A ton of motherboards are being fried by the board being overloaded by current flowing back from the 12v line.
A ton? Show me links to that. Motherboards get fried when people run five or six gpus with unpowered risers each trying to draw 2-3 amps or more. Do you even understand how a powered riser works? There is no "current flow" back to the motherboard. The USB lines handle data, the molex provides 12v and 5v (converted to 3.3 for pice spec).
Seriously? You're selling a product and you decide responding like an asshole is the best approach? Why not try asking someone to clarify instead of assuming they don't know wtf they are talking about?
Here's more information on the issue, which yes, is an issue.
https://litecointalk.org/index.php?topic=10232.0http://forum.feathercoin.com/index.php?topic=2193.0There's no reason for the 12v to be connected when you're added an extra powered 12v connection. That's the entire point of the powered riser. You're either burning up the board by drawing too much power without powered risers, or you're burning it in reverse if the 12v pin is connected at the board. This is why people are modifying ribbon cables to resolve this issue.