OK the simple way to understand. It's the way the ram works with each other. AMD Mobo's are dual channel ram . The intel 1155 is dual channel ram. The 1366 is tri channel. The not yet released 2011 will be quad channel ram.

PCI-E is your GPU slot or other things. Mainly as GPU. Right now we are using PCI-E 2 but it is rumoured that the new 2011 mobos will be able to have PCI-E 3. That would be the next generation of GPU's.

All it means is a bit more efficient speed in ram and GPU use. But I don't think that the average user would notice it much.