The CPUs used on the X300 can have up to 24 PCIe 3.0 lanes, if both SSDs take 8 lanes together + 1 for the wifi card that makes 9 lanes all together, maybe an extra lane for the sound chip, the usb Ports on the X300 are as far as I know directly from the CPU. This circumstances leave 15 to 16 lanes unused. I wonder why asrock did not add some PCIe to usb chip, to add more usb ports, or maybe an additional m.2. which is more accessible from the outside for e.g. under a lid, for easyer adding of an eGPU.