Therefore CX4 Gigabit are backwards compatible

FiberYes CX4 Gigabit is an IEEE specification for 10 Gigabit over coaxial cable, intended to connect servers, switches and storage over short distances of up to 15 metres/50 feet. 10GBase-CX4 or 802.3ak uses the Infiniband 4X connector to maximize signal Adding to a robust family of 10 Gigabit Ethernet Adaptors, Intel is now offering the Intel 10 Gigabit CX4 Gigabit Port Server Adaptor. Following the 802.ak specification, the Intel CX4 Gigabit Port Server Adaptor offers the lowest cost per port of all the current 10GbE interconnects. The low-profile Small Tree Communications, an industry leader in providing state-of-the-art networking solutions, today announced the immediate availability of software support for the Intel? 10 Gigabit Ethernet CX4 Gigabit Port product for Apple’s Intel processor-based systems running Mac OS X version 10.5 “Leopard.” This solution provides network transfer speeds up to 10 Gb/sec,Upgrading their network with Intel’s 10GbE CX4 server adapter will ultimately allow them to effectively take on a wider range of projects.” Adds Steve Modica and affordable way to significantly increase their workflow”.