There are security issues with PCIE cable
PCIe I / O interface, 16x is = 164pin; rated power = 25 ~ 75 W (12V = 5.5A; 3.3V = 3.0 + 0.4A);
Unfortunately, such as USB data cable testing requirements, should be proposed by the pci-sig specifications, has not yet appeared!
So the product of the wire is not 164pin, never to buy! Otherwise, once the product has a problem, the user is difficult to argue with the manufacturer!
Because they must remove the power supply and signal matching the required wire, this will not only change the PCIe specifications, but also cause failure and disaster!
There is a technical information here
You can refer to
https://smallformfactor.net/forum/threads/the-pcie-flexible-riser-card-has-standard-features-from-li-heat-ltd.1534/