TrustedReviews have looked at the Xbox 360 HD DVD Drive

The HD DVD drive is designed to stand next to the Xbox 360 if it’s positioned upright, or sit on top of it if your console is laid flat. The HD DVD drive matches the finish of the X360 perfectly, so despite being a separate unit it’s still aesthetically pleasing. The drive requires an external power supply which comes in the box, but thankfully it’s far, far smaller than the console’s gargantuan power brick.

Xbox 360 HD DVD Drive Review