Head-to-head · Best Portable SSDs

ACASIS USB4 40Gbps NVMe Enclosure vs OWC Express 1M2

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

The short answer

OWC Express 1M2 comes out ahead by a clear margin (3.8 vs 4.6). The gap is mostly about power users who need high-speed external storage — read the strengths below before deciding.

Ranked #6 in Best Portable SSDs

ACASIS USB4 40Gbps NVMe Enclosure

3.8

$79

The ACASIS TBU405 Air delivers strong real-world performance for users needing fast external NVMe storage at a budget-friendly price point. My Tech Grid reviewer Everett Ashford praised its consistent sustained speeds and thermal control during long transfers, calling it a solid pick for video editors and photographers. The unit supports Thunderbolt 4/3 and USB4 with active cooling, making it ideal for power users on M1/M2 MacBooks and Windows laptops. However, Reddit users noted the fan noise under load and lack of encryption/RAID features may be drawbacks for enterprise users. Best for creative professionals who want Thunderbolt speeds without the premium cost, but those needing quiet operation or advanced features should consider alternatives.

Strengths

— Supports Thunderbolt 4/3 and USB4 with up to 40Gbps transfer speeds
— Active cooling system with fan and thermal pad ensures sustained performance under heavy load
— Tool-free installation for M.2 NVMe drives with support for 2280, 2260, 2242, and 2230 sizes

Watch-outs

— Fan is audible during sustained heavy use
— No hardware encryption or RAID capabilities
— Some early firmware polish needed for maximum compatibility with older USB ports

$79 · Check Price on Amazon Full review →

Higher ratedRanked #2 in Best Portable SSDs

OWC Express 1M2

4.6

$219

PCMag's Tony Hoffman and PCWorld's Jon Jacobi both praised the OWC Express 1M2 for its exceptional USB4 performance, noting over 3GBps transfer speeds and universal compatibility across USB and Thunderbolt ports. The reviewers highlighted its versatility and sturdy construction, though Jacobi noted it's somewhat large and pricey when preloaded with an SSD. The device's unpopulated design allows users to install their own NVMe drive, making it a flexible option for those wanting USB4 performance without the premium cost of preloaded models. This product is ideal for power users who need high-speed external storage but should be avoided by those prioritizing portability or budget-conscious buyers.

Strengths

— Over 3GBps transfer speeds with USB4 interface
— Works with all USB and Thunderbolt 3/4 ports for universal compatibility
— Available unpopulated so users can leverage their own NVMe SSD

Watch-outs

— A bit pricey when loaded with an SSD
— Large size may be cumbersome for portability

$219 · Check Price on Amazon Full review →

How they stack up

ACASIS USB4 40Gbps NVMe Enclosure

The ACASIS USB4 40Gbps NVMe Enclosure outperforms the ASUS ROG Strix Arion in terms of Thunderbolt 4/3 support and active cooling, making it ideal for creative professionals. However, it's less aesthetically pleasing than the OWC Express 1M2 and lacks hardware encryption, which the OWC offers. Compared to the Plugable USBC-NVME, it provides better performance and compatibility but at the cost of fan noise and a more complex installation process.

OWC Express 1M2

The OWC Express 1M2 excels in performance and universal compatibility, surpassing the ASUS ROG Strix Arion and ACASIS USB4 40Gbps NVMe Enclosure in transfer speeds and portability. However, it's larger and more expensive than the Plugable USBC-NVME and Sabrent Rocket Nano V2, making it less ideal for users seeking compact and budget-friendly options. Compared to the ORICO M2VG01-C3, it offers better performance but lacks the transparent design that tech enthusiasts might prefer.

Specs side-by-side

Spec	ACASIS USB4 40Gbps NVMe Enclosure	OWC Express 1M2
Interface	Thunderbolt 4/3, USB4	USB4
Speed	Up to 40Gbps	Over 3GBps
Capacity	Up to 4TB	1TB
Form Factor	2280, 2260, 2242, 2230	External SSD
Dimensions	100 x 68 x 15 mm	100 x 57 x 15 mm
Weight	110 g	100 g
Compatibility	M1/M2 MacBooks, Windows laptops	USB and Thunderbolt 3/4
Material	Aluminum Alloy	Aluminum

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