It’s a much faster conduit for file transfer and video: 10 Gbps (gigabits per second), which is about twice as fast as USB 3.0 and 20 times faster than USB 2.0.
The tech was developed by Intel alone.
Thunderbolt Technology: The Fastest Data Connection to Your PC.
Thunderbolt can work on both data streams at the same time and in
both directions and it seems to get the full 10 Gbps of rated bandwidth,
in each direction. This is what gives the technology the advantage
over the USB 3.0 of today.
Besides the speed benefits, Thunderbolt technology will allow users
to continue to use thinner notebooks without sacrificing potential
performance of devices - though I would wager to say that USB
connections aren't much bigger and this same feat could be accomplished
Intel says that Thunderbolt was designed with professional
audio and video applications in mind where low latency and highly
accurate time syncs are critical.
And since the technology is
compatible with current DisplayPort displays, there should be a healthy
stock of available displays that will support this technology today.
(At least for display output purposes...)
First, it provides a DisplayPort display link drawn out from the Intel Flexible Display Interface. This means that it can display video from the IGP or anything that routes through it, this is most common in Laptops with switchable graphics. Some implementations allow it to be plugged in to a discrete video card but this requires some additional wiring, this is most common on Desktops since Thunderbolt hasn't been integrated into the Intel chipset yet, nor has it been integrated into any video cards.
Second, it combines 4 PCIe 2.0 lanes into a single high speed data link. Since Thunderbolt hasn't been natively integrated into the PCH yet these PCIe lanes are canibalized from the PCIe lanes that would normally serve the 1x and 4x slots on the motherboard.
Both the data and video links can be demultiplexed and handled by one or more Thunderbolt devices along the way, or by a single DisplayPort display at the very end.
If this sounds like it's basically USB 3.0 with video then that wouldn't be far off from a consumer standpoint.