Mac USB 3.0 'Cards' Via ThunderBolt Cable

The notion of adding a USB 3 card to your Mac is largely obsolete. With Apple completely abandoning any Mac Pro models with internal PCIe slots in 2014, the already small market for add-on USB cards is collapsing. As such, this page won't see much in the way of updates. USB 3.X cards for Mac is seeing fading and rapidly shrinking demand.

The alternative to adding a USB 3.0 'expansion card' to a Macintosh is by taking advantage of a ThunderBolt port's direct access to the PCI bus. While there are several ThunderBolt to PCIe card chassis on the market, their cost-benefit is hard to justify when far cheaper ThunderBolt to USB 3 adapter cables and docking stations are available that don't involve a USB 3.0 PCI or Express card at all.
           
Multi-Port TBolt HubCheap USB 3.0 AdapterThunderBolt 2 Dock
Akitio Thunder Dock

USB3 + eSATA + FW800
Kanex ThunderBolt USB3 Adapter

USB 3.0 Port + Gigabit Ethernet
ThunderBolt 2 Dock

3 USB3 Ports + More

Above we have Akitio's ThunderBolt hub which is ideal for legacy storage devices like USB 3.0 / 2.0, eSATA and FireWire drives. Kanex offers two versions of it's USB 3.0 ThunderBolt dongle: With a USB 3.0 port and either a Gigabit Ethernet jack or an eSATA drive connector. Lastly, the latest multi-port dock from Belkin supports 2nd-generation 20Gpbs ThunderBolt 2 Macs and features video, audio in/out, Ethernet as well as 3 total SuperSpeed USB 3.0 ports. It's backward compatible with older 10Gbps ThunderBolt Mac systems as well.

USB3 CARDS FOR OLDER MACS

LaCie is leading the Mac USB 3 market for owners of Intel Macintosh Pro towers with PCI slots - and for now discontinued MacBook Pro models with ExpressCard/34 slots built-in. LaCie offers optimized USB 3 Drivers for Mac OSX Lion and Leopard 10.5+ to go with these Mac compatible USB3 cards: The driver currently only supports LaCie brand USB3 drives - at this time. You MUST pair LaCie products for a working USB 3 backup drive solution.

For PCI-e Mac Pro Towers:
LaCie USB 3 PCI Express Card - Model 130977

For 15"-17" MacBook Pro ExpressCard Slots:
LaCie USB 3 ExpressCard/34 - Model 130998

For external hard drives LaCie supports with their USB 3 adapter cards, it is essential to match the cards with LaCie SuperSpeed drives from their current product lineup.

Alternately, CalDigit and Sonnet Technologies offers Mac SuperSpeed USB3 drivers specifically written for their USB 3 cards BUT they work with a wider variety of 3rd-pary drives. So, unlike LaCie, the drivers are more 'universal' and not locked to their own brand of drives.
Apple Compatible USB 3 Gear From CalDigit

Sonnet Technologies joined the Mac SuperSpeed market with it's pair of cards:
Sonnet Allegro USB 3 PCIe Card USB3M-E
Sonnet USB 3 ExpressCard/34 USB3-2PM-E34
Sonnet Drivers for Mac OSX 10.6+ are available here.

PCI Cards and ExpressCard USB 3 Adapters

Nec Japan NEC Japan recently announced a USB 3 controller, backwards compatible with USB 1.1 and USB 2.0 due to arrive at retail mid to late year - supporting USB3.0 Superspeed (5Gbps) along with the older 480Mbps, 12Mbps, and the 1.5Mbps specifications.

To get a good sense of the speed bump SuperSpeed USB will provide, NEC's press release compared the transfer a 25GB Blu-ray disc from disc to a computer hard drive: 70 second transfer with USB3.0 interface as compared to 14 minutes with USB 2.0 - Quite impressive! It's cards like these that will likely show up in Mac Pro Towers first.

ExpressCard 2.0 Spec To Support USB SuperSpeed

Current ExpressCard specs just couldn't support USB3's full bandwidth - it's current theoretcial bandwitdh is only 2.5Gbps. So in many ways, the next generation -- ExpressCard 2.0 -- had to wait for USB 3 specs to finalize before it's final architechture and needs could be spec'd out. It too will be backward compatible.

It'll be interesting to see how this will play out on Mac computers. Apple recently completely REMOVED the ExpressCard slot on 15" Unibody MacBook Pro's, opting for an SD slot instead. That leaves only the current 17" model still supporting Express-Cards at all. And without SuperSpeed drivers in OSX Leopard, the future of USB 3 on the Mac is still unclear.

But in the meantime, the Windows market is getting interesting, and some people are already enjoying the benefits of SuperSpeed with PCI USB3 cards, USB 3 backup drives that are taking advantage of the USB3 drivers Windows now offers.