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Green circuit board with silver PCIe connector and single USB-C port on metal bracket

STARTECH

STARTECH PEXUSB321C 1-Port USB 3.2 Gen 2x2 PCIe Expansion Card

SKU CH-YTBC-K6FD6 MPN PEXUSB321C

Adds a USB-C port delivering 20Gbps over a PCIe 3.0 x4 slot with UASP support for NVMe drives

  • TypePCI Express to USB Card
  • External USB PortsUSB Type-C (24 pin, Gen 2x2, 20Gbps)
  • StandardUSB 3.2 Specification Rev. 1.0 PCI Express Base Specificatio
  • Data Transfer Rate20Gbps
  • Operating Systems SupportedWindows 8, 8.1, 10 Windows Server 2012 R2, 2016, 2019 macOS
  • CompatibilityPCI Express enabled computer or server with a PCI Express x4
  • Add a 20Gbps USB-C port with USB 3.2 Gen 2x2
  • ASMedia ASM3242 controller handles mixed-speed devices efficiently
  • UASP support speeds up external NVMe storage
  • Fits full-height or low-profile PCIe 3.0 x4 slots
  • Works on Windows, macOS and Linux without extra drivers

Single-port USB 3.2 Gen 2x2 PCIe card

The StarTech PEXUSB321C adds one USB Type-C port with 20Gbps bandwidth to a desktop or server. It installs in a PCI Express 3.0 x4 slot and uses the ASMedia ASM3242 host controller. Windows, Linux and macOS are supported with automatic driver loading on Windows 8 and later. The card includes both full-height and low-profile brackets.

Builders needing one 20Gbps USB-C data port

Suits users who want a single high-speed USB-C connection for external SSDs, NVMe enclosures or other Gen 2x2 devices. UASP support improves storage throughput on compatible drives. Not for systems lacking a PCIe x4 or larger slot, nor for anyone requiring DisplayPort Alt Mode or USB Power Delivery charging. The port delivers up to 15W of power for bus-powered peripherals only.

Requires PCIe 3.0 x4 for full 20Gbps speed

The card’s maximum throughput is limited by the host bus interface. PCI Express Gen 1 slots cap bandwidth at 10Gbps, while Gen 2 or Gen 3 x4 links are needed to reach the rated 20Gbps. Verify the motherboard or riser provides at least a Gen 2 x4 connection before purchase.

Highlights

  • Add a 20Gbps USB-C port with USB 3.2 Gen 2x2
  • ASMedia ASM3242 controller handles mixed-speed devices efficiently
  • UASP support speeds up external NVMe storage
  • Fits full-height or low-profile PCIe 3.0 x4 slots
  • Works on Windows, macOS and Linux without extra drivers

Specifications

BrandStarTech.com
ModelPEXUSB321C
TypePCI Express to USB Card
External USB PortsUSB Type-C (24 pin, Gen 2x2, 20Gbps)
StandardUSB 3.2 Specification Rev. 1.0
PCI Express Base Specification Rev. 3.0
Intel xHCI Specification Rev. 1.1
UASP (USB Attached SCSI Protocol) Rev. 1.0
Data Transfer Rate20Gbps
Operating Systems SupportedWindows 8, 8.1, 10
Windows Server 2012 R2, 2016, 2019
macOS 10.13 to 10.15, 11.0
Linux 3.5 or later LTS version only
CompatibilityPCI Express enabled computer or server with a PCI Express x4 slot or higher (x8, x16)
Note:
The card's USB-C ports are standard data throughput port. They do not support DP Alt Mode or USB Power Delivery.
The maximum throughput of this card is limited by the bus interface. PCI Express Gen 1.0 max throughput is 10Gbps. A PCI Express Gen 2 or Gen 3 port is required to reach speeds up to 20Gbps.
SpecificationsPorts: 1
Interface: PCI Express x4
Bus Type: PCI Express
Card Type: Standard Profile (LP bracket incl.)
Chipset ID: ASMedia - ASM3242
Maximum Data Transfer Rate: 20Gbps
Type and Rate: USB 3.2 Gen 2x2 (20Gbps)
UASP Support: Yes
MTBF: 3,126,209 Hours
FeaturesUSB 3.2 Gen 2x2 PCIe card has 1x USB Type-C port supporting SuperSpeed 20Gbps
Host controller card with ASMedia ASM3242
USB-C PCI Express expansion card supports Multiple INs for max bandwidth w/mixed-speed devices
Adapter card w/UASP support optimizes USB performance w/ SSDs/HDDs/NVMe drives
Up to 15W of power
Install add-on card in full or low-profile PCI-e 3.0 x4 slot
Win/Linux/macOS w/auto drivers on Windows 8 and up
Supports all older USB 3.1/3.0/2.0 devices
Dimensions0.9" x 3.1" x 2.0"
Weight1.3 oz.
Package ContentsPCI Express USB Card
Full Profile Bracket (Installed)
Low Profile Bracket
Quick-Start Guide
Shipping weight0.10 kg
Package size170 × 142 × 30 mm

Questions about this item

Does the card include a low-profile bracket or only the full-size one?

Both brackets are supplied; the full-profile bracket comes pre-installed and the low-profile bracket is included for slim chassis.

Which PCI Express generation is needed to reach the 20Gbps headline speed?

A PCIe 2.0 or 3.0 x4 slot is required; a PCIe 1.0 slot caps throughput at 10Gbps.

Can the single USB-C port deliver the full 20Gbps when an NVMe enclosure is attached?

Yes, the ASMedia ASM3242 controller supports Multiple INs so mixed-speed devices share the 20Gbps bandwidth without bottlenecking the NVMe drive.

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