A while ago I purchased a 320gb hdd for my media center. When it arrived Windows recognised it as being 298gb in size. I didn’t quibble – I wish I did now.

Recently I replaced it with a 500gb drive by the same company – Western Digital – but Windows recognises it as being only 465.76gb in size.  Where’s my other 35gb?

I’ve been caught by one of those 500gb = 500,000,000,000 bytes (500x1000x1000x1000).  If you do the maths properly, you get 500,000,000,000/1024/1024/1024 = 465.66gb.

In other words, if you are in the market for a new drive, steer clear of Western Digital. I used to like Maxtor drives, but I switched because Maxtor were more expensive than the competition, but now I wish I’d stuck with them. It seems Maxtor were charging more because they were giving you the actual drive size – not an imaginary number.

Update: Even my Maxtor drives are doing it now: I have 2 40gb maxtors in this machine of varying ages and they both report differing amount of available space.  One is 39.6gb in size and the other is 38.1gb. Neither quite 40gb but both above the 40,000,000,000 mark:-(