BH5 refers to a "type or make of chip" your ram is "made of". Ram which uses BH5 chips can operate with very low timings/latencies. It can OC very well usually, it likes "extra" voltage (vdimm) and will run "faster" at higher voltages.
As for HyperX A or non-A, don't know about it specifically. Link the other posts you're trying to understand and someone can help.
Fern
EDIT: I see have an AMD 64 system. You're likely worrying needlessly. Generally waste of money to pay for expensive LL ram with those (very little performance diff in a 64bit system. See Zebo's benchies)