Your Coral USB Accelerator doesn’t keep the USB ID it boots with. It shows up as 1a6e:089a and switches to 18d1:9302 after Frigate’s first inference, so a Proxmox mapping keyed to the first ID points at nothing. A PCIe USB card for Proxmox passthrough fixes that. You hand the VM a whole USB controller, and anything plugged into its ports belongs to the guest, whatever ID it shows.
This guide picks six cards for USB controller passthrough, from a four-controller StarTech built to feed up to four VMs to a $25 card for one Home Assistant VM. You’ll see each card’s real controller count, the passthrough reports for each chip, and a slot and IOMMU checklist to run through before you buy. I rechecked every maker spec sheet and Amazon listing in October 2026, so the counts and price bands below match what’s on sale now.
Pick a PCIe USB card for passthrough
The number that decides everything is how many USB host controllers sit on the card. With a PCIe card, Proxmox passes a controller, not a port. One controller means one VM gets every port, and four controllers means four VMs can each own one. Prices are Amazon bands from late October 2026, so check the live price before you order.
| Award | Pick | Why it wins | Approx. price |
|---|---|---|---|
| Best overall | StarTech PEXUSB3S44V | Four Renesas controllers, one per port, so up to four VMs | About $85 to $95, check on Amazon |
| Best for two VMs | StarTech PEXUSB3S42V | Two controllers, two ports each, same chip family | About $75 to $85, check on Amazon |
| Best budget | FebSmart FS-U4-Pro | One Renesas controller on an x1 card, no power cable | About $24 to $30, check on Amazon |
| Best 10 Gbps | StarTech PEXUSB314A2V2 | Two ASM3142 controllers, four 10 Gbps ports | About $110 to $125, check on Amazon |
| Cheapest 10 Gbps | StarTech PEXUSB312A3 | One ASM3142, two ports, both brackets in the box | About $35 to $45, check on Amazon |
| Best USB-C | Sonnet Allegro USB-C 4-Port | Two ASM3142 controllers, no power cable, Linux 6.6 or later | About $145 to $155, check on Amazon |
If you run one Home Assistant VM with a Zigbee stick and a Coral, the FebSmart is enough. You only need the four-controller StarTech when another VM wants USB hardware of its own, such as Frigate in its own guest or a Z-Wave stick elsewhere.
How these cards were chosen
Speed barely matters for a Zigbee coordinator, while the controller layout decides whether passthrough works at all. So the shortlist is ranked on facts you can check yourself: specs come from the maker pages and Amazon listings, and passthrough reports come from the forum threads cited inline:
- You get the controller chip and count from the maker’s own spec page, never from an Amazon title.
- You get a live, in-stock Amazon listing for the exact part number, read through Amazon’s API on the day of writing.
- You get the public passthrough reports for each chip family from the Proxmox forum, vfio-users and Level1Techs, with their limits stated.
Inateck’s Fresco FL1100 cards were on the first list and dropped off, because no US listing was in stock in October 2026. Generic seven-port cards went too. Without a maker datasheet you can’t tell which chip you’re buying, and the chip is the whole point.
Compare the cards side by side
Read the controllers column first. Ports per controller tells you how the card splits between your VMs, and the slot column tells you whether it fits your board.
| Card | Controllers | Ports | Slot | Aux power | Low-profile bracket |
|---|---|---|---|---|---|
| StarTech PEXUSB3S44V | 4x Renesas uPD720202 | 4x USB-A 5 Gbps, 1 per controller | x4, PCIe 2.0 | SATA or Molex, optional | Yes |
| StarTech PEXUSB3S42V | 2x Renesas uPD720202 | 4x USB-A 5 Gbps, 2 per controller | x4, PCIe 2.0 | SATA or Molex, optional | Yes |
| FebSmart FS-U4-Pro | 1x Renesas | 4x USB-A, 5 Gbps shared | x1, PCIe 2.0 | None | Yes |
| StarTech PEXUSB314A2V2 | 2x ASMedia ASM3142 | 4x USB-A 10 Gbps, 2 per controller | x4, PCIe 2.0 | SATA, optional | No |
| StarTech PEXUSB312A3 | 1x ASMedia ASM3142 | 2x USB-A 10 Gbps | x4, PCIe 3.0 | SATA, optional | Yes |
| Sonnet Allegro USB-C 4-Port | 2x ASMedia ASM3142 | 4x USB-C 10 Gbps, 7.5 W each | x4, PCIe 2.0 | None | No |
Five of the six need an x4 slot in your board. Many small boards only have an x1 slot free once a GPU or an HBA takes the long one, and then the FebSmart is the only card here that fits. The PCIe lane guide shows how to read your board’s slot wiring before you choose.
Split four VMs with the StarTech PEXUSB3S44V
Who it suits: you run Home Assistant and Frigate in separate VMs, maybe a third guest with a Z-Wave stick, and each one should own its USB hardware. It is the only card on this list with a controller behind every port.
StarTech’s spec page says the card uses “four host controller chipsets”, so each port gets its own 5 Gbps channel. Every controller is a Renesas uPD720202, and each one should appear to Proxmox as a separate PCIe device. The card needs an x4 slot and takes optional SATA or Molex power for up to 900 mA per port. Both bracket heights are in the box, Linux is on StarTech’s compatibility list, and a firmware updater sits on the same page.
Pass on it if only one VM needs USB, because you’d pay about $60 extra for controllers you never split. Nobody has shown the full trick in public yet, either. A Proxmox user on the pve-user list bought this card for its chipset, but no public report shows all four controllers in four VMs at once.
The spec supports it, so check the IOMMU groups on your board the day the card arrives. Expect about $85 to $95, and check the live price on Amazon.
Feed two VMs with the StarTech PEXUSB3S42V
Pick this one when you have exactly two guests that want USB. That is usually Home Assistant with its Zigbee radio and a Frigate VM with the Coral. You get the same Renesas chip as the four-controller model, split as two ports per controller.
StarTech lists 5 Gbps per pair of ports, an x4 connector, SATA and Molex power inputs and a low-profile bracket. The two ports that share a controller always go to the same VM, so plan which device sits where before you mount the card. It saves only about $10 over the four-controller model, and Amazon listed it as low stock in late October 2026.
It is the wrong card for you if the price gap closes, because the PEXUSB3S44V is then the better buy for the same slot. StarTech’s page also lists only Windows for this model, while the four-controller card lists Linux. It uses the same xHCI chip the kernel already drives, but that’s our inference, not StarTech’s promise. Expect about $75 to $85, and check the live price on Amazon.
Start cheap with the FebSmart FS-U4-Pro
This is the card for you if you run a single Home Assistant OS VM, maybe with Frigate as an add-on, and want its Zigbee stick and Coral off the host’s USB. It is also the card for boards with only an x1 slot free.
FebSmart’s manual covers what you need to know before it goes in the slot:
- You get a Renesas USB 3.0 host controller, though the manual doesn’t name the exact part.
- You can fit it in any slot from x1 to x16, since it uses a PCIe 2.0 x1 interface.
- You share 5 Gbps across all four ports.
- You don’t route a power cable, because FebSmart says each port gets 5 V and 2 A from the slot.
A driver listing for the low-profile sibling, the FS-U4L-Pro, shows a uPD720201. Treat the 2 A figure as a per-port ceiling, not four loads at once: four ports at 10 W each would be 40 W, far above what a PCIe x1 slot is specified to deliver. A Zigbee stick and a Coral are fine, but a bus-powered hard drive belongs on a card with a SATA lead. Pass on it if you’ll ever want a second VM on USB, because one controller cannot be split.
One uPD720201 report on Level1Techs is worth knowing. After a firmware flash, a Windows guest hung at the UEFI logo when a device was plugged in at boot, while empty ports booted fine. That was Windows, not Home Assistant OS, but it’s a good reason to test a cold VM start with your stick attached on day one. Expect about $24 to $30, and check the live price on Amazon.
Add 10 Gbps ports with the StarTech PEXUSB314A2V2
Choose it when one of your two guests also needs fast USB storage, such as a backup VM writing to an external SSD. You get two controllers and four 10 Gbps ports on one card.
The spec page lists two ASMedia ASM3142 controllers behind an ASM1812, with each controller’s 10 Gbps shared by two ports. It wants an x4 slot, takes optional SATA power, lists Linux support and carries StarTech’s lifetime warranty. Neither a Zigbee radio nor a Coral needs 10 Gbps, so the extra money only pays off when a disk shares the card.
Leave it on the shelf if your server is a low-profile case, because it ships with a full-height bracket only. The chip family has a history too. Its predecessor, the ASM1142, was reported on vfio-users in 2017 to stop working after a guest crashed, until the host rebooted. No such report turns up for the ASM3142 itself. Expect about $110 to $125, and check the live price on Amazon.
Save on 10 Gbps with the StarTech PEXUSB312A3
It fits you best with one VM, two devices and a small case. You get one ASM3142 controller, two 10 Gbps USB-A ports and both bracket heights in the box.
StarTech builds it to the PCIe 3.0 spec with an x4 connector and notes that a Gen 1 slot caps the throughput. Power comes from the slot or an optional SATA cable, and Linux is on the list. For USB-C devices, the PEXUSB312C3 is the same single-controller design with two USB-C ports, for about $40 to $50.
You will outgrow it if you need more than two ports. A USB 3 hub on a passed-through port works, but it puts your Zigbee stick next to more USB 3 traffic, so use a powered USB 2.0 hub for the radio instead. Against the FebSmart, you trade two ports and the x1 fit for speed your smart-home radios will not use. Expect about $35 to $45, and check the live price on Amazon.
Go USB-C with the Sonnet Allegro 4-Port
Who it suits: your devices are moving to USB-C, your power supply has no spare SATA lead, and two VMs share the card. It’s the priciest pick here, and you pay for slot-only power and Sonnet’s documentation.
Sonnet lists two ASM3142 controllers on a PCIe 2.0 x4 interface, 20 Gbps combined, 7.5 W per port and no power connector. Its Linux note asks for kernel 6.6 or later, which every current Proxmox VE kernel clears. Check your serial when it arrives. Sonnet says serials starting “A” used the older ASM1142, while serials from “B” onward, shipping since July 2020, use the ASM3142.
Pass on it if you have a low-profile case, because the card is full-height only. The Amazon listing calls it “Allegro Pro”, while Sonnet’s page names the same part USB3C-4PM-E without “Pro”, so match the part number on the box. Expect about $145 to $155, and check the live price on Amazon.
Understand USB controller passthrough in Proxmox
Proxmox passes USB in two ways, and the card only matters for the second. Plain USB passthrough maps one device into the VM by its vendor and product ID, or by bus and port path. The Proxmox VE manual notes the port path depends on the order of the host’s USB controllers, so it is not as fixed as it looks.
PCI passthrough gives the VM the controller itself, and the guest’s kernel enumerates whatever is plugged in. A Zigbee stick alone usually works fine with ID mapping, since its ID never changes and Proxmox attaches it as soon as it appears. A controller earns its slot in three cases:
- You use a Coral USB Accelerator, which the Frigate docs show switching from
1a6e:089ato18d1:9302after its first inference. - You plug in two radios with the same vendor and product ID, so an ID mapping can’t tell them apart.
- You want the board’s own USB ports left to the host, including the keyboard you’d use to rescue it.
That last case is why an add-in card beats passing the motherboard’s controller. One Proxmox forum user found their Intel onboard controller worked only on the VM’s first boot, because it had no reset mechanism. Their add-in Fresco card survived Windows guest reboots but died after a macOS guest shut down, so no chip family gets a clean bill of health from forum posts alone.
If you’re moving Frigate from Coral to Hailo, the question changes. Hailo accelerators are M.2 or PCIe cards, so they skip the USB controller entirely.
Check these things before you buy
A card that looks perfect on paper can land in an IOMMU group with your NIC or SATA controller. Then you can’t pass it without passing them too. The Proxmox PCI(e) passthrough page says the device needs its own IOMMU group, though sharing one with its root port or bridge is fine. Go through this list with your board’s manual open:
- You’ve confirmed that IOMMU or VT-d is enabled in the firmware setup.
- You know whether your free slot is x1 or x4, and whether it’s wired to the CPU or the chipset.
- You’ve counted the VMs that need USB, and the card has at least that many controllers.
- You have a spare SATA or Molex lead if the card wants one, or you’ve picked a slot-powered card.
- You’ve matched the bracket height to your case, because two of these cards are full-height only.
- You have a shielded extension cable or a powered USB 2.0 hub ready for the Zigbee stick.
The chipset slot is the part that trips people up. Alex Williamson’s explainer on IOMMU groups shows how every device below a bridge without ACS lands in one group. On some boards, the x1 slot hanging off the chipset shares a group with half the board, and Proxmox’s advice is to try another slot.
If your mini PC has no slot at all, the Home Assistant mini PC guide covers the boxes worth running HAOS on directly.
The extension cable matters as much as the card. Home Assistant’s ZHA docs warn that USB 3 ports, devices and unshielded cables interfere with 2.4 GHz radios. Zigbee2MQTT adds that a 50 cm extension is already enough to help. The ZHA docs go further and tell you to use a USB 2.0 port only, or a powered USB 2.0 hub when a computer has nothing but USB 3. Every card here has USB 3 ports, so put the coordinator on a powered USB 2.0 hub plugged into one of them, with a shielded cable, away from the Coral and any SSD.
The Zigbee coordinator guide covers which stick to buy, and ZHA vs Zigbee2MQTT helps you pick the stack that reads it.
For the host side, the Proxmox post-install checklist covers repositories and updates, and the GPU passthrough guide uses the same IOMMU checks for a graphics card.
