Most importantly, the specification is designed to be compatible with existing hardware and software. Included in the specification are standardized cables and connectors for the entire gamut of link widths from 1x to 16x and supports signaling rates of 2.5GTps (giga transactions per second). The External Cabling specification standardizes the use of PCIe technology over copper cable, defining connector retention, identification, labeling, cabling attributes, and identification. The result will be "PCIe solutions for IO expansion drawers, external graphics processors, tethered mobile docking, communications equipment and embedded applications." "This specification helps the industry create new products that will take PCIe technology out of the box," according to PCI-SIG chairman Al Yanes.
Those are the kinds of possibilities opened up by the External Cable specification.
Now imagine sticking a pair of graphics cards into an external enclosure with its own power supply and fan, hooking your monitor to that, and connecting it to your PC or even a laptop. In addition, the need for large heat sinks and fans often means that you lose a second slot to a single PCIe graphics card. Newer GeForce and Radeon graphics cards can emit a lot of heat while demanding a significant amount of power under high load. Once you get past the price tag, the biggest barriers for many who would want to deploy a dual SLI or Crossfire system are heat, power, and space. The most obvious application for the new standard is external enclosures for graphics cards.
Dubbed the PCI Express External Cabling specification and approved by the PCI Special Interest Group (PCI-SIG), version 1.0 extends PCIe outside of the case. This provides auxiliary power options for these and future devices. While installing the new head unit, I added new fuse panels for the power leads going to the Harman/Kardon Drive+Play for switched and un-switched 12v power and ground. A new PCI Express standard has been approved that will allow for the development of and operation of external PCIe graphics cards. Non-Metallic Single Gang Switch and Outlet Box.