While I’m sure many people are aware of this, it was something I hadn’t ever investigated until yesterday.
My main machine is a Mac Pro (2010) which has a total of 5 USB ports. That might seem like a few, however two are on the front and I’d prefer to leave those available for external hard drives and USB sticks. Having only 3 on the back isn’t really enough. Currently I run 3 USB hubs to connect everything and this was starting to run low too. (Mouse, keyboard, USB sound, printer x2, scanner, card reader, external hard drive, hard drive dock, iPod cable, etc) I figured I might as well grab a 4 port USB express card while ordering a few other thing from OWC the other day. The model is the Allegro USB PCIe USB 2.0 Adapter Card for PCI Express. (link here)
What I hadn’t thought about was that my Mac Pro motherboard has full-sized slots and the card is a small slot. After googling a bit, I couldn’t find a definite answer to the question “can I just install it anyway since it physically will allow insertion?”. Well, for anyone else wondering the same thing, yes you can. Below is a photo of it looking a little strange in the slot, but it works. Install was simple. Undo the two thumb screws holding the securing metal plate, insert the card, put the plate back on, boot the computer and it works straight away. No drivers needed.