what exactily is quad pumped vs dual channel

for example, if i have a DDR400 that means my throughput is

400M * 2 (1 transfer in each clock edge) * 32 bit / 8 = 3.2 GB/s

is the 2x transfer per clock cycle what is called double pumped?

so how is pentium 4 platform quad pumped? does is have a 64 bit wide
Bus ?


How about dual channel? i know it means that you need RAM chips in
pairs, and interleaving is used, right? it allows both chips to be
acessed at the same time, but the bus this has to be 64 bit wide?