Each data line uses two pins/wires (USB signals are transmitted using differential signaling on a USB 2.0 and earlier are half-duplex (there is only one data line).

This means there are separate send and receive data lines.

USB 3.0 and later are full-duplex (bits can be transmitted in both directions simultaneously).

Considering protocol overhead, you may see up to approximately 3.2 Gbps or 400 MB/s.

This is similar to PCIe 1.0 x2 or PCIe 2.0 x1 (not including PCIe protocol overhead). This is 5 Gbps using 8b/10b encoding which means bytes are transferred at 4 Gbps or 500 MB/s (not including USB protocol overhead).

USB 3.0 transfers bits on the wire at SuperSpeed (SS).

Also known as USB 3.1 gen 1 and USB 3.2 gen 1 x1.

This occurs even with Apple's built-in USB 3.0 ports, so it isn't your card.

There are warning messages upon waking from sleep when using detachable USB media in OS X.

The USB 3.0 Asmedia ASM1042A chipset has native drivers included in 10.9 and newer.

The Lexar USB 3.0 memory reader is known to be unreliable with several Fresco Logic cards.

Cards using other chipsets require proprietary drivers. 10.7.5 Lion through 10.10 Yosemite is supported through the open source GenericUSBXHCI driver.

Due to USB 3.0 ports in the nMP, native drivers are provided in OS X for Fresco Logic FL1100 chipset cards in ML 10.8.2 or later.

Transferring data over USB 3.0 interferes with bluetooth reception and to a lesser extent 2.4Ghz Wi-Fi.

The cMP will never boot from USB 3 or newer because there is no support until the drivers load in the OS.

The USB 3.0 cards in the list are not limited to storage-only USB devices (exceptions to this are noted).

The USB 3.0 cards in this list do not require supplemental power to be attached.The USB 3.0 cards in this list support UASP for faster transfer speeds and reduced CPU utilization (exceptions to this are noted).This thread refers to PCIe cards for adding USB 3.0 and 3.1 to classic Mac Pros. Thread summary for latest recommendations.

Do i need drivers ffor usb 3 card