It's XP compatible, the Sabrent website says:
USB 3.0 4-Port PCI Express Card / XP/Vista/7/8 32-Bit And 64-Bit
If I can't get one of these to work, I guess a hub will be my next option.
I have an old Windows XP x86 machine that I use for retro gaming and a few other such things. I need more USB ports, so I've been trying to install a USB expansion card, but haven't had any luck. I'm on my second attempt now, using a Sabrent CP-4PTU PCIe card. I know it's got power running...