So you can install x8 or x16 cards into the slot and still operate them, albeit at a reduced speed. For example, the P35 Express chipset has 22 total PCIe lanes (16 on the P35 NB, 6 on the ICH9/R SB). There simply aren't enough available lanes to provide two full x16 ports. Instead, they fit one of the x16 physical ports with x4 electrical (data) lanes. This allows you to use Crossfire if you're so inclined, or to install PCIe RAID adapters, etc.
Most PCIe cards can fall back to smaller lane widths if the full width isn't available. My x8 Areca controller supports x8, x4, or x1--and I'm running it at x4 in my P35-based board. Greg > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:hardware- > [EMAIL PROTECTED] On Behalf Of Anthony Q. Martin > Sent: Wednesday, September 19, 2007 2:52 AM > To: The Hardware List > Subject: [H] PCI-e x16 vx PCI-e x16 (electrical x4) > > What does that mean? Obviously, the second is not a "real" pci-e 16 > slot, though the mobo slot looks identical. Why would one want this?
