OWC Express 4M2 Ultra Announced – DIY Thunderbolt 5 NVMe RAID up to 6,622 MB/s

by Alexandra ThompsonApril 28^th, 2026

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At NAB 2026, OWC unveiled the Express 4M2 Ultra, a compact DIY four-slot NVMe enclosure that the company says is the first certified Thunderbolt 5 solution of its kind. It accepts up to four user-supplied M.2 SSDs, supports RAID 0/1/4/5/10 and JBOD, delivers real-world speeds rated at up to 6,622 MB/s, and starts at $399.99.

We caught up with Larry O’Connor, OWC’s founder, on the show floor for a closer look. Larry framed the new unit as a meaningful upgrade over the company’s original Express 4M2, a Thunderbolt 3 enclosure that became a customer favorite and whose user feedback shaped the redesign. He told us the result is a sleeker, more compact product with no current equivalent on the market, and it joins recent OWC storage releases, including the Envoy Ultra Thunderbolt 5 portable SSD and the Express 1M2 80G USB4 SSD we have previously covered.

A DIY Thunderbolt 5 RAID, finally

The Express 4M2 Ultra is positioned as a successor to OWC’s original Express 4M2 from the Thunderbolt 3 era. Larry described the new unit as a DIY solution that lets users install up to four M.2 2280 NVMe drives, with sustained throughput he pegged at over 6,000 MB/s in conversation. OWC’s published specification sheet puts the figure more precisely at up to 6,622 MB/s with PCIe 4.0 or 5.0 SSDs in RAID 0, and adds support for the shorter M.2 2242 form factor. RAID 0, 1, 4, 5, 10, and JBOD are all supported via SoftRAID or any third-party utility.

The enclosure remains backward compatible with Thunderbolt 4, USB4, and Thunderbolt 3 hosts at reduced speeds, so it will not become dead weight when shared between an older travel machine and a newer studio workstation.

Capacity today, capacity tomorrow

With current 8 TB M.2 NVMe drives, the Express 4M2 Ultra reaches 32 TB in a single enclosure. Larry told us 16 TB M.2 drives are now hitting the market at a premium price point, which would push a single unit to 64 TB. OWC’s official materials stop at 32 TB per unit and quote 128 TB as the headroom across four daisy-chained enclosures.

The user-serviceable design is also a hedge against today’s volatile flash market: users can fit two drives now and add the rest later, or swap in larger SSDs as they become available, all without replacing the enclosure itself.

Thermal and acoustic design

The Express 4M2 Ultra is wrapped in an aluminum body (described as aircraft-grade in OWC’s press materials) that handles most heat dissipation passively. A smart adaptive fan engages only when sustained workloads push thermals past what the chassis can absorb on its own. A blue LED indicates power and can be switched off, while soft per-drive activity indicators glow through the housing, a small but practical detail when troubleshooting an array of identical-looking M.2 sticks.

According to Larry, acoustic engineering is part of a longer arc dating back roughly 15 years, when Macs went near-silent and made storage devices the new noise floor. We have seen that lineage in OWC’s ThunderBlade family, shipping since 2017, and the Express 4M2 Ultra brings that thinking down into a smaller, user-serviceable package.

The downstream Thunderbolt 5 port matters more than it looks

The second Thunderbolt 5 port on the back of the enclosure may be the more interesting design choice. According to Larry, on a Thunderbolt 3 or Thunderbolt 4 setup at 40 Gbps, daisy-chaining a 4K display behind a high-speed storage device causes the display to claim priority bandwidth, dropping a 1,500 MB/s drive to somewhere between 800 and 1,200 MB/s in real-world use. Thunderbolt 5 reserves an additional 40 Gbps dedicated to video on top of its 80 Gbps base, for a combined 56 Gbps of display headroom. In Larry’s example, a single Thunderbolt 5 dock can therefore drive two 6K displays and a ThunderBlade X12 simultaneously without the display chain encroaching on storage bandwidth.

The Express 4M2 Ultra carries that same downstream port. OWC’s spec sheet adds that it allows up to five additional Thunderbolt devices plus one USB peripheral to be daisy-chained, including further Express 4M2 Ultra units combined as a single volume.

A frank conversation about flash pricing

According to Larry, NAND flash has risen roughly 10x or more since around May 2024, and even compared to August 2025, OWC has seen real costs on SSDs climb four to five times. The driver, in his view, is the AI data center build-out and the circular flow of capital among a small group of hyperscalers, all building as if each will end up at the top of the pyramid. Spinning hard drives have only risen by 5 to 15%, with helium supply pressures (impacted by ongoing geopolitical conflict) the main input cost.

The practical takeaway is that workflows that casually defaulted to flash for everything a year or two ago now warrant a more deliberate split. OWC’s own direct-attach Thunderbolt spinning drive arrays sustain over 1,500 MB/s in RAID 5, sufficient for most 4K and even 6K RAW workflows. That makes Flash a tool to deploy where it pays off (ingest, active editing, scratch) rather than the default for every byte. Larry sees some signs of stabilization in recent weeks, while still calling the current picture “ugly.”

Price and availability

The OWC Express 4M2 Ultra is available for pre-order now at $399.99 for the enclosure alone and $549.99 with a three-year SoftRAID Premium license bundled. According to Larry, units pre-ordered now should reach customers as early as late May, with mass availability through OWC’s channel partners and Amazon scheduled for mid-June through early July. OWC’s official press materials describe the broader shipping window as Q3 2026. For complete specifications and pre-order, see OWC’s product page for the Express 4M2 Ultra.

Are you investing in a Thunderbolt 5 RAID this year, or is current flash pricing pushing you back toward spinning storage for the bulk of your workflow? Let us know in the comments!