Bandwidth for PCIe 1x is 250 [500]* MB/s
- Note 1 - Since PCI Express is a serial based technology, data can be sent over the bus in two directions at once. Normal PCI is Parallel, and as such all data goes in one direction around the loop. Each 1x lane in PCI Express can transmit in both directions at once. In the table the first number is the bandwidth in one direction and the second number is the combined bandwidth in both directions. Also please note that in PCI Express bandwidth is not shared the same way as in PCI, so there is less congestion on the bus.
USB 3.0 is also known as Super Speed
The new SuperSpeed mode has a transfer rate of 4.8Gbps
Real word speeds of 3.0 will be different depending on the chipmaker implementation, device connected and the chip it uses, and OS