my laptop has an Intel 5 series/3400 series chipset dated 2009, I bought a PCI express card with 2 USB3 slots and discovered not enough power comes through it to run a USB 3 external hardrive, nor a USB2 external hard drive. USB 3 external hard drives only come with one connector, USB2 external bus powered hard drives come with 2 ( USB 2 hard drives also usually have a slot for a separate USB2 power connector, The USB3 drive doesnt have that either. But I note the PCI express card does have one. With the data cable connected to the PCI express card and the supplementary power cable connected to a USB2 port it works fine, and the USB3 hard drive also works fine connected to a single USB2 port. This tells me there is not enough power coming through the PCI express bus. Checking the site www.expresscard.org I discover there is PCI express 1 and now PCI express 2, which has more power, enough to run USB3. But I cant seem to find anywhere that says whether my chipset is PCI express 1 or 2!
I like to have more details about your motherboard model or specifications. What is the model number of the chipset on your computer? Can you run the chipset ID utility?