Running Mbox 2 Pro here on Windows 10(with PT 12.4) connected to the on-board FW port(Asus X79 Sabertooth, i7 3930K, 32GB of RAM). The only issue I ever have is that sometimes PT won't find the Mbox(a restart solves it every time)
Search eBay for "firewire card TI chipset"(without the quotes). Look for a card that has a FW400 port(so you won't need to adapt from FW800) and get the proper style card for your PC(look at your available slots so you know to get a PCI card(long slot) or a PCIe card(short slot)