In Cinebench 11.5 all cores loaded, one Intel Haswell core w/o HT is roughly equal to two Piledriver cores (or one module).
Really the only time Piledriver is worth it is if you KNOW you are going to be using those cores hard all the time.
Or if you don't game hard enough, or on heavily cpu dependent games, enough to need anything faster. Pretty much everything else happens instantly on either one given a decent SSD.