All hard drives are not created equal, at least when it comes to adding one to your Xbox 360 or PlayStation 3.

The reason a 120GB hard drive for the 360 costs $180 compared to just $45 for one you could put in your PS3 is that the 360's drive has been tweaked to specifically suit the Microsoft console, reports MTV.

The drive comes pre-loaded with Xbox Arcade trials as well as "specific Gaming Instructions and some levels of the OS," says Krishna Chander of iSuppli. The 360 drives have also been color tuned and packaged for the addition to your console, as opposed to a generic hard drive that you could add to your PS3.

iSuppli guesses that the prepped 360 drives are then sent along to a Value Added Retailer, which applies casing and packaging before tacking it its own fee and sending the drives along to Microsoft. Estimating the markup, iSuppli figures that Microsoft might be paying as much as $100 for a 360 hard drive.

Microsoft then suggests a price for retail, which in this case is $180. Is that a fair price for the ability to simply plug it in and have it work?

Image courtesy Microsoft