PCStats has already seen what the Western Digital Raptor brings to the table, and now we'll take one of the largest hard drives on the market for a spin. Meet Western Digital's 400GB Caviar SE16 hard drive, model number: WD4000KD. Be sure to check out the Experts Tips on how to ensure the best possible performance from the Western Digital Caviar SE16 WD4000KD hard drive, a little later in the review. The Western Digital Caviar SE16 WD4000KD supports the 150MB/s Serial ATA I standard, and sports a mammoth 16MB onboard cache buffer.