1. There is no FSB. On an LGA 1155 motherboard, everything runs off the BCLK (100 MHz). Memory has a multiplier, and the motherboard comes with a maximum multiplier.
2. There is no northbridge or FSB! Intel moved some of the northbridge functions onto the CPU, the rest were moved to what used to be the southbridge (they call it the PCH now). The memory communicates directly with the CPU, because that's where the memory controller is now. So there's no longer any FSB limitation on the memory.