Performance-wise, it is necessary to confirm the specific model number (example in bold WD5000BEKT-XXXXXXX) in user benchmarks otherwise you can end up with a Black that is only equivalent to a Blue if that is higher density (thus overcoming lower RPM) and yet effectively pay a premium per GB for it. The depletion of older inventory and the transition to higher density across all/i] production lines of even the same model name can take a long time. Unfortunately, this makes mail-order a crap shoot as the specific model is not specified (akin to a CPU stepping). I don't know if there is such variance in current 500GB models.