PCI expansion slots
These are older slots that do not support the full 4800 Mb/s superspeed connection. They do however support up to 2000 Mb/s. That’s still over 4 times the speed of USB 2.0! If your computer only has these slots you can still upgrade to USB 3.0.
PCI Express (also known as PCIe) expansion slots
These are the most common slots on newer motherboards manufactured in the last couple of years. These expansion slots come in different sizes; x1, x4, x8 and x16. The bigger sizes are intended for components like graphics cards because they require more data channels.
The good news is that the majority of USB 3.0 PCIe cards are of the x1 size, which means that it can slot into ALL PCIe slots, no matter the size. In other words a x1 card can fit into a x4, x8 and x16 expansion slot.
Check what version of PCIe slot your motherboard supports
The original PCIe version was v1.0 and this does not support the new USB 3.0 speeds. Therefore make sure your motherboard supports PCIe version 2.0 and above. You can find this out by checking the documentation online for your computer’s motherboard. Sometimes the version is written on the motherboard next to the expansion slot.
Other points to note:
Some new usb 3 pci cards require power from your computers power supply. See the different power cables you may need here.