TestFreaks posted a review on the ASUS U3S6 USB 3.0/SATA 3 6Gbps PCIE Card
A quote from the article:
>> ASUS U3S6 USB 3.0/SATA 3 6Gbps PCIE Card Review
I've taken a look at a couple USB 3.0 PCIE card here at TestFreaks. I've got another one today, but this one is quite a bit different. It's the ASUSU3S6 PCIE card that actually uses a standard PCIE slot as opposed to the small X1 style. This card is also a combo card that has both USB 3.0 ports on it and SATA3 or 6Gbps SATA connections on it. According to ASUS, utilizing the PCIE X4 slot will maximize your bandwidth or speeds you'll achieve with USB 3.0. let's find out if that's true or not
>> ASUS U3S6 USB 3.0/SATA 3 6Gbps PCIE Card Review