Power consumption of up-to-date graphics cards have risen from around 60W to about 160W in the last three years and it is highly likely that this trend will continue. Even though PCI Express 2.0 is set to overcome the current power consumption limits, PCI special interest group (PCI SIG) is working on a standard for add-on cards that fit into current platforms, but consume up to 300W.
PCI SIG recently announced that it was working on electromechanical specification of PCI Express add-on cards that addresses graphics power and thermals greater than those supported by PCI Express CEM 1.1 and PCI Express 150W 1.0. Its purpose is to provide additional capabilities for PCI Express graphics within the existing framework of an evolutionary strategy that is based on existing motherboard form factors.
Currently both ATI Radeon HD 2900 XT and Nvidia GeForce 8800 GTX/Ultra fit into present PCI Express 1.1/1.0a specification. As is known, according to PCI Express 1.0a standards, a device that consumes maximum of 150W should consume maximum 75W from the mainboard’s slot and maximum 75W from power supply unit’s PCI Express connector. The GeForce 8800 GTX/Ultra has power consumption of about 130W and while it devours more than 80W of power from power supply unit (PSU), it uses two connectors, which means that there should be no problems. The Radeon HD 2900 XT consumes approximately 160W and uses one 6-pin and one 8-pin connectors while sucking up to approximately 110W from a PSU, according to measurements by X-bit labs. However, exact specifications for graphics cards that consume more than 150W and more than 75W from PCI Express connector are not defined.
The new PCI Express 225W/300W graphics card electromechanical specification is primarily designed to deliver additional electrical power to a PCI Express graphics add-in card and provide increased card volume for the management of thermals, according to a statement by PCI SIG.
The 30-day member review for the version 0.5 draft specification ends on Wednesday, June 6, 2007.