You'd be right - sort of. The "thin back" does not allow for the PCI riser card to be installed, or any additional cards. The "fat back" allows for a single PCI slot riser plus a CommSlot II riser - which would be housing an ethernet card. What do you do with the additional PCI slot? Ideally a FW/USB card, but mine doesn't work - found a patch though I need to test - so it's usually a USB 1.1 card in there.
I'm missing the CommSlot riser on mine
, but at least I can put large files onto it using a USB stick.JB