As if the fight for supremacy between Thunderbolt and USB 3.0 weren't bad enough, it now looks like a third contestant might enter the ring. That contestant is none other than the PCI Special Interest Group (PCI-SIG), the consortium that oversees the PCI Express specification. According to EE Times, PCI-SIG will soon "launch an effort" to create a new cable standard derived from the PCIe 3.0 spec.
This cable standard will reportedly be targeted at consumer applications. It will involve cables and connectors "flatter" than those currently used for Thunderbolt, and it should enable transfer speeds of up to 32Gbps (4GB/s). By contrast, Thunderbolt currently tops out at 10Gbps, or 1.25GB/s, per channel. EE Times doesn't expect the upcoming PCIe cable spec to be complete for another two years, though, so I'm guessing Thunderbolt could get a speed boost by the time the first derived products hit stores.
Why a new standard? None of the details seem to be official right now, but EE Times quotes a source that says cabled PCIe 3.0 presents advantages for ultra-thin laptops and tablets. Thunderbolt is "interesting," the source claims, but the controller chips required to support it "don't make business sense." PCI-SIG's standard would be open and presumably cheaper to implement.
Running PCI Express through cables isn't a new concept, by the way. PCI-SIG already has a PCIe External Cabling spec, although it's based on an older, slower version of the standard. EE Times says that spec is geared for servers and data centers.