Well, the first few japanese models were built thinkin the HDD would come on the outside, so all they had was a pc card slot. But they figured a way of organizing everything inside to allow enough room for the HDD as an internal addon, so they redesigned the layout for the US release. Since then, the Japanese model has followed suit, and now I believe both to be layed out the same way. Kinda like the 1st generation Playstations were different than other models too. For example the audio/video ports were different in the original Playstations as compared to models that came out afterwards. Simple things that make things smaller and cheaper and more useful, I suppose.