The SB850 is the south bridge chip. mobos have a northbridge and a southbridge. Usually the NB is advertised, and the SB is kinda forgotten. I think NB handles, CPU, memory and graphics as main functions, whereas SB deals with networking, sound, and some of the PCIs (I might be wrong , though).
the other options are transcend, mushkin (mushkin is kind of expensive and i have to order it from a different online shop that is much further away it is more effort and the transport cost might be quite hefty) and corsair but the corsair ram is very expensive