I have NAS4Free running on an HP ProLiant Microserver G7 N40L/N54L. The Microserver only has USB 2.0 ports, so I’m thinking of purchasing a PCIe card so I can use a USB 3.0 hard drive at full speed. How can I tell what cards are compatible?

I figure the yes/no in each case will depend on the chipset the card uses. From my research so far, it looks like it’s the xHCI driver that talks to the USB controller. (See 17.4. USB Storage Devices, and the xhci man page.)

Is this something that even needs to be checked? Or do all USB 3.0 chipsets have to present a uniform interface, such that a single generic driver (xhci) handles all?

If there are compatibility issues, does NAS4Free support all the chipsets that FreeBSD does? The latest NAS4Free,, is based on FreeBSD 10.1-RELEASE.


I resolved the issue (I now have a functional USB3 add-in card in my NAS4Free box). If someone else can explain how to tell which cards work in general, I'll be happy to accept your answer.

Based on FreeBSD Compatible USB 3.0 PCIe Cards, I installed a Syba 4 Port USB 3.0 PCI-e 2.0 x1 Card (SD-PEX20137). It works once I remembered to connect the Molex power.

I was hoping I could also use the card to boot from my USB3 thumb drive, but apparently that's a no-go.

you cannot boot via the BIOS on any device that is an ‘add-in’ device, unless it is a PCI card that also contains an option ROM...

Unfortunately, I am not aware of any USB 3.0 add-in cards which have their own Option ROMs that allow you to boot from their USB 3.0 ports.

source: Why can't I boot from the USB 3.0 ports on my PCI add-in card?

  • 1
    FWIW, I'm doing a spot of testing and bought a couple of random USB 3.0 cards from eBay, one with the VIA chipset, and another with the Reneas chipset. The VIA arrived first and I plugged it into the obvious x1 slot and it wasn't bootable, but when the Reneas arrived I had to pop it into another slot and discovered it was bootable. Swapping the cards made the VIA bootable and the Reneas non-bootable, showing it was the slot, not the cards.
    – mr_jrt
    Mar 12 '16 at 20:32
  • (Cont'd) This may (probably) be a quirk of my motherboard (a Gigabyte 990FXA-UD5 with a built-in Etron USB 3.0 controller), but I thought it worth mentioning that people stumbling across this in the future might want to try using different slots.
    – mr_jrt
    Mar 12 '16 at 20:32

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