That is not what I said. A write cache merely caches the data in RAM. It does not speed up media writes. The speed of writes is due to a combination of hardware + driver in almost all cases. (I can't think of times where that is not the case, but I say "almost" since there may be other factors that have slipped my mind or of which I am unaware. )So write-caching is not an advantage or something possible in FreeBSD.