It is my understanding that all PCIe is backward compatible, or at least that's what I gather from the information overload I get on Wiki about it.
However, I decided to look at a motherboard with PCIe slots, and, PCIe x16 is small, but PCIe 2.0, and 3.0 is big.
So I'm guessing backward compatible in this case means a graphics card meant to be plugged into PCIe x16 can be plugged into a PCIe 2 and 3, but a graphics card meant to be plugged into a PCIe 2 or 3 will not fit into a PCIe x16.
So the PCIe slot on the MoBo should always be equal or higher than the device your plugging in, and never the reverse.
Have I got that right?
OK, the next question is, how to interpret how many PCIe slots I am getting in a motherboard.
Take this motherboard for example.
PCI Express 3.0 x16: 2 (single @ x16 or dual @ x8)
PCI Express 2.0 x16: 1 @ x4
PCI Express x1: 2
PCI Slots: 2
I don't understand the single and the dual, and I don't understand @x16, @x8, @x4 thing.
Edited by RB_Kandy, 28 June 2012 - 02:22 AM.