If you run into problems with any of your risers, I've found that in probably 99% of the cases I've had problems it was their cheap USB cable, not the riser or the PCI connector.  Although I've phased out my riser use, towards the end I just bought 1.5ft USB cables for all my risers and swapped them regardless if I had problems or not.  Saved me a bunch of hassle in the long run...