The current generation of Intel’s Thunderbolt interface is based off a controller known as “Cactus Ridge”. Cactus Ridge can provide 10 Gbps of bandwidth in both directions per channel. The current Thunderbolt connection allows for the transmission of both Display Port and either 2 or 4 PCI express Gen 2 lanes depending on the controller.
The successor to Cactus Ridge is the third generation of Thunderbolt, “Redwood Ridge”. Redwood Ridge will be available in mid 2013 for the Intel LGA 1150 Haswell platform and will still be 10 Gbps of bi-directional bandwidth. The only difference with Redwood Ridge is the addition of Display Port 1.2 support.
2014 sees the big leap forward for Thunderbolt. “Falcon Ridge” will bring a healthy 20 Gbps of bi-directional bandwidth per channel. Doubling the bandwidth of current second and to be released third generation Thunderbolt controllers. It has been questioned whether Intel will be able to achiev 20 Gbps speeds using copper cables. A transition to optical fibres may be required to reach the new doubled bandwidth, although this could add even more cost to the already costly Thunderbolt cable.
Intel had planned to release optical cables for Thunderbolt this year, but due to the high cost they have limited such a market expansion to the enterprise market. Currently a Thunderbolt controller costs PC and motherboard makers around $20 while the final price for a finished Thunderbolt cable (copper based) is around $50. The high price of Thunderbolt cables and devices is currently keeping Thunderbolt adoption low.
