StarTech.com

StarTech Thunderbolt 3 PCIe Expansion Chassis

Expert rating5.5 / 10

Connection Standard:: Thunderbolt 3
PSU Wattage:: External adapter, single 6-pin PCIe power connector
Max GPU Length:: Compact chassis, best suited to smaller single/dual-slot cards

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Manufacturer: StarTech.com Last updated: 2026-10-08

StarTech Thunderbolt 3 PCIe Expansion Chassis Review

StarTech TB31PCIEX16 Thunderbolt 3 PCIe expansion chassis bare DIY eGPU enclosure DisplayPort

StarTech's TB31PCIEX16 is a no-nonsense, DIY-oriented PCIe expansion box aimed as much at general PCIe card expansion as at gaming, but it's a long-running fixture of DIY eGPU guides because of its compact size and built-in DisplayPort passthrough for GPU video output. It skips laptop charging entirely and its single 6-pin power connector limits it to lower-wattage cards, so it fills a narrower niche than dedicated gaming enclosures like the AKiTiO Node.

Overview

The TB31PCIEX16 provides one open PCIe x16 slot behind a Thunderbolt 3 connection, along with a DisplayPort output that lets an installed graphics card drive an external monitor directly through the enclosure. Power comes from an external adapter feeding a single supplemental 6-pin PCIe connector, which caps the enclosure's practical GPU support to smaller, lower-power cards rather than flagship-class hardware.

Comparison to Alternatives

It occupies similar territory to the AKiTiO Node and ADT-Link UT3G as a bare, bring-your-own-GPU box, but its single 6-pin connector gives it noticeably less power headroom than the Node's larger internal supply, and unlike the ADT-Link UT3G it doesn't use the newer, higher-bandwidth USB4/ASM2464PDX chipset. It also lacks the 100W host laptop charging that enclosures like the Razer Core X or Sonnet Breakaway boxes include.

Our verdict

Reviewed by Burooj Alam. Rated by us, not by users.

Expert rating5.5 / 10

A capable, inexpensive DIY PCIe expansion box, but its limited power delivery and lack of laptop charging make it a compromise pick next to purpose-built gaming eGPU enclosures.

Best for

DIY builders wanting a compact bare Thunderbolt 3 PCIe enclosure
Users pairing the box with lower-power single or dual-slot cards
Buyers who specifically need built-in DisplayPort video passthrough

Not for

Anyone wanting to run a high-wattage flagship GPU
Laptop users who want the enclosure to also charge their machine
Buyers wanting the newest USB4/Thunderbolt 4 chipset bandwidth

Specifications

What these specs mean

Identity

Brand	StarTech.com
Model Number	TB31PCIEX16

Connectivity

Connection Standard	Thunderbolt 3
Extra Ports	1

Power & Compatibility

PSU Wattage	6 W
Cooling Type	Passive chassis venting; relies on the installed card's own cooler

FAQs

What are the key specifications of the StarTech Thunderbolt 3 PCIe Expansion Chassis (TB31PCIEX16) (Bare PCIe x16 Slot / DisplayPort Video Output / DIY GPU Enclosure / External Power Adapter)?

Key specs for the StarTech Thunderbolt 3 PCIe Expansion Chassis: Connection Standard Thunderbolt 3, Extra Ports 1x DisplayPort 1.2 video passthrough, Cooling Type Passive chassis venting; relies on the installed card's own cooler, PCIe Slot 1x PCIe 3.0 x16, Ports Thunderbolt 3, DisplayPort.

Who is the StarTech Thunderbolt 3 PCIe Expansion Chassis (TB31PCIEX16) (Bare PCIe x16 Slot / DisplayPort Video Output / DIY GPU Enclosure / External Power Adapter) best suited to?

Best suited to: DIY builders wanting a compact bare Thunderbolt 3 PCIe enclosure; Users pairing the box with lower-power single or dual-slot cards; Buyers who specifically need built-in DisplayPort video passthrough.

What are the drawbacks of the StarTech Thunderbolt 3 PCIe Expansion Chassis (TB31PCIEX16) (Bare PCIe x16 Slot / DisplayPort Video Output / DIY GPU Enclosure / External Power Adapter)?

Not the best fit for: Anyone wanting to run a high-wattage flagship GPU; Laptop users who want the enclosure to also charge their machine; Buyers wanting the newest USB4/Thunderbolt 4 chipset bandwidth.