I know it's a late reply, but I couldn't help saying something. This drive is definately 5400 rpm hence WD calling it green. If the drive spins slower, the rate at which data is accessed is slower. To counter this, the drive has a big cache, which acts like fast ram, which can hold more data. The end result is a drive that uses less power and has a fast access time. I recommend any drive, which has a massive cache.