How do I determine the nominal memory bandwidth of my system?

I'm running some (not so new) Linux distribution. I want to determine what the memory bandwidth of my system is - not the effective bandwidth I can get from benchmarking/testing - but the _nominal_ bandwidth, given my board, CPU sockets, memory channels and RAM DIMMs. I should mention that when I try to figure this out in my head I always get the calculations mixed up: gigabytes verus gigabits, transactions per seconds vs bytes per second, the number of channels vs the number of DIMMs etc. Note: If possible, assume I don't have utilities such as lshw or inxi installed.