MSI is planning to refresh its X99S series with the X99A lineup, which will introduce support for USB 3.1. This new USB standard offers a bandwidth of up to 10Gbps.
One confirmed model from the new lineup is the X99A Gaming 9 ACK. This board offers two USB 3.1 type-A ports, which are 100% backwards compatible with USB 3.0 and USB 2.0, and are driven by an ASMedia ASM1352R controller. This chip is wired to the X99 PCH over PCI-Express 2.0 x2, which is just enough bandwidth for 10 Gb/s downstream.
AnandTech did some preliminary testing with the MSI X99A Gaming 9 ACK motherboard and reports the new standard offers big performance increases versus USB 3.0.