As we already explained, video card with PCI express 2.0 support can also work in PCI express 1.1 slots , simply the data transmission speed in this case will be lowered. In addition PCI-SIG at present develops certain electromechanical specifications, which will allow the powerful video cards ( PCI express 2.0 generation ) to work in motherboards, which support only PCI express 1.1. In a word, compatibility from the physical and electrical parameters must be provided.
However, nuances in use of video card with interface PCI express 2.0 with motherboard using PCI express 1.x exist.
The motherboard asus series blitz on base of chipset intel p35, that use a special chip crossLinx to realize crossfire support using : PCI express x8 + PCI express x8, have the limited video cards compatibility, by supporting the PCI express 2.0 system bus . In particular, the primary slot PCIEX16_1 corresponds to the requirements PCI express 1.1, and therefore it allow to install video card with PCI express 2.0 interface . However, the second slot PCIEX16_2 support only PCI express 1.0/1.0a requirement ; therefore if user install on it a video card with PCI express 2.0 interface ,the system will not be able to recognize not only this video card, but also the simultaneously installed in the primary slot PCIEX16_1.
In a word, the owners of motherboard asus series blitz must install a video card with interface PCI 2.0 only in the primary slot PCI express x16, designated as BY PCIEX16_1. It should be noted that similar limitations is only on motherboard series blitz, which use the special chip crossLinx. Other motherboard asus on base of chipset intel p35 support video card with PCI express 2.0 interface without any problems.