At the present moment we know that video card with support of interface PCI express 2.0 will have eighth pin power connector and the maximum power is not more than 300 W. We already published the photographs of video card series radeon x2900 XTX compatible with interface PCI express x16 from the existing generation, although the combination of the power cable is made from 8 + 6 pins connector . As it was explained, similar video card can be connected to two 6 pin power connector - main matter is the power unit witch must have a sufficient capacity along the line +12 v. The chipset with support of PCI express 2.0 will be released only in the second half-year.
It is Known also that video card with interface PCI express 1.x can be installed in the slot PCI express 2.0 motherboards, in this case it will work at its rate of data exchange .
Fortunately, on the pages of PCI-SIG it is completely clear : new PCIe 2.0 adapters running at of 5.0 GT/S can be plugged in the existing PCIe slots and run at the slower rate with 2.5 GT/S. SO it becomes clear that video card with interface PCI express 2.0 can work in motherboards with slot PCI express x16 from the generation PCI express 1.x, but only at speed 2.5 GT/s. This is completely regular, since old chipset does not support the doubled speed of data transmission .
This compatibility has the obvious nuance, connected with video card power. Since the systems with support PCI express 1.0 are capable of ensuring to video card only 150 W and video card of class PCI express 2.0 are capable of consuming up to 225-300 W power, in the case the association of new video card class high-end and old motherboard require all existing to video card power connector . We already spoke about this. all will depend in the power of power unit and supported current strength along the line +12 v.