StarTech.com

StarTech.com StarTech U.2 to PCIe 4.0 x4 Adapter for 2.5in U.2 NVMe SSD

Name: StarTech U.2 to PCIe 4.0 x4 Adapter for 2.5in U.2 NVMe SSD, SFF-8639, TAA | OS independent, For NVMe U.2/U.3 drives only, Up to 15mm height, Vented
Brand: StarTech.com
SKU: B072JK2XLC

Bottom line: The StarTech U.2 to PCIe 4.0 x4 Adapter for 2.5in U.2 NVMe SSD: Runs U.2 NVMe SSDs in any PCIe 4.0 x4/x8/x16 slot without a backplane; main trade-off: NVMe U.2/U.3 drives only; SATA and SAS protocols are not supported.

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By Mike Perry, Founder & Editor-in-Chief · Listing data updated 2026-10-21

Mike Perry — Hardware researcher since 2014. For retro PC hardware and period-correct parts, synthesises manufacturer documentation, community compatibility lists and marketplace listings rather than first-hand lab testing. Core beat: GPU performance across gaming, rendering, and local-LLM inference. About the author →

Pros & Cons

Pros

✓ Runs U.2 NVMe SSDs in any PCIe 4.0 x4/x8/x16 slot without a backplane
✓ Vented full-profile bracket plus PCB cutout to curb thermal throttling
✓ Driver-free and OS independent across Windows, Windows Server, and Linux
✓ Backwards compatible with PCIe 3.0 x4/x8/x16 motherboard slots
✓ Two-year StarTech.com coverage with free 24/5 multi-lingual tech support

Cons

✗ NVMe U.2/U.3 drives only; SATA and SAS protocols are not supported
✗ Drive height capped at 15mm, ruling out thicker enterprise U.2 units
✗ Full-profile bracket only, so low-profile and SFF cases need another option
✗ Single-drive card; each additional U.2 SSD consumes another PCIe slot

SpecPicks Verdict

SpecPicks scored StarTech U.2 to PCIe 4.0 x4 Adapter for 2.5in U.2 NVMe SSD using a rating × review-volume × price-fit model applied to published specs and reviews across the retro graphics & video category. StarTech.com's retro graphics & video lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.

Common buyer scenarios for retro graphics & video of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.

Key Features

HIGH PERFORMANCE U.2 STORAGE: Add a 2.5 inch U.2 NVMe SSD into a PCIe 4.0 x4/x8/x16 slot in a desktop or server, enabling ultra-fast data access; Supports SFF-8639 drives up to 15mm in height; For NVMe U.2/U.3 drives only; SATA/SAS protocols not supported
UNIVERSAL COMPATIBILITY: Backwards compatible with PCI Express 3.0 motherboards that have an available x4, x8, or x16 PCIe slot; U.2 Adapter works with all workstation and server operating systems such as Windows, Windows Server, and Linux
PREVENT OVERHEATING: Vented full-profile bracket and a large cutout in the PCB allow for better airflow and heat dissipation, which helps maintain optimal and reliable performance while reducing potential thermal throttling
HASSLE-FREE SETUP: Pre-installed full-profile bracket & included drive mounting screws enable the connection of a U.2 drive to a PCIe slot, without the need of a drive backplane or additional cables; The U.2 to PCIe Card requires no drivers or software
THE IT PRO'S CHOICE: Designed and built for IT Professionals, this U.2 to PCI Express Adapter Card is backed for two years, including free lifetime 24/5 multi-lingual technical assistance

Full Specifications

Brand	StarTech.com
Style	U2 to PCIe
Style Name	U2 to PCIe
Unit Count	1 Count
Model Number	PEX4SFF8639
Compatibility	Linux
Built-In Media	drive adapter card (1), drive-mounting screws (4), quick-start guide (1)
Item Type Name	U.2 to PCI Express Adapter
Mfr Part Number	PEX4SFF8639
Compatible Devices	The U.2 to PCIe adapter is compatible with PCIe 3.0 motherboards and is also backward compatible with PCIe 2.0 and PCIe 1.0.
Hardware Interface	PCI
Warranty Description	2 Years
Item Dimensions L x W x H	6.5"L x 4.8"W x 0.9"H
Global Trade Identification Number	00065030872591
Full listing title	StarTech U.2 to PCIe 4.0 x4 Adapter for 2.5in U.2 NVMe SSD, SFF-8639, TAA \| OS independent, For NVMe U.2/U.3 drives only, Up to 15mm height, Vented full-profile bracket, SATA/SAS not supported

Ready to buy?

StarTech U.2 to PCIe 4.0 x4 Adapter for 2.5in U.2 NVMe SSD, SFF-8639, TAA | OS independent, For NVMe U.2/U.3 drives only, Up to 15mm height, Vented full-profile bracket, SATA/SAS not supported is vintage hardware; the used and vintage market on eBay carries most of the live inventory. Prices and condition vary by seller and move in real time, so we link the live listing rather than quote a cached price. It also has an Amazon listing — check it for current price and availability. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.

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