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Meet the Fastest OWC SSD Ever Built – the Accelsior 4M2

OWC Accelsior 4M.2

High-performance M.2 NVMe SSD solution delivers 6,000MB/s real-world speed for the 2019 Mac Pro and PC Towers.

OWC today announced the all-new Accelsior 4M2 ultra high-performance PCIe M.2 NVMe internal SSD that delivers over 6,000MB/s real-world speeds in capacities up to 8TB. The Accelsior 4M2 is the fastest SSD ever built by OWC and is the perfect storage solution for large format video editing, VR/AR/MR environments, extreme gaming, compute-intensive applications and other high bandwidth needs.

Incredible Versatility 

Whether you have the Mac Pro 2019, a Mac Pro 2012 or 2010, or PC tower, the Accelsior 4M2 delivers the blazing performance, unstoppable reliability and stunning versatility that are the hallmarks of OWC’s brand reputation. As a half-length x8/x16 compatible card, this game-changer offers true versatility, so users can install it in full-length PCIe 3.0 or 2.0 slots as well. Even Thunderbolt 3-equipped laptops can experience the performance boosting benefits of Accelsior 4M2 with Plug-and-Play ease using the OWC Mercury Helios 3S PCIe expansion chassis (sold separately). In other words, it’s incredibly versatile.

Insane Performance

Accelsior 4M2 offers the fastest data rates ever delivered by an OWC SSD.

Accelsior 4M2 was designed to address each of its four NVMe blade style drives at full x4 PCIe speeds, so whether users are running a single drive on the Accelsior 4M2 or running four in JBOD, each drive has the capability to run at full speed. Oh, and if over 6,000MB/s of real-world speed and 8TB of capacity isn’t enough to meet the task, users can RAID two Accelsior 4M2 cards together to experience out of this world exponential performance. With NVMe SSDs powering its heartbeat, Accelsior 4M2 offers the fastest data rates ever delivered by an OWC SSD. In other words, it’s insanely fast.

Easy and Complete Drive Health Monitoring, TRIM, and Performance Management

Accelsior 4M2 includes SoftRAID Pro to ensure you get the maximum, steady performance, protection and monitoring against drive failure, and plug and play simplicity. SoftRAID is the only solution with robust drive health monitoring and reporting capabilities and full TRIM support for attached external and PCIe slot NVMe drives under MacOS. SoftRAID’s easy setup makes it customize storage to the RAID volume(s) your applications need by helping you through the entire process. Ready to go Plug-and-Play or just decide what you’re use requirements are for desired RAIDs and how much space to allocate to it. It’s that simple to create your preference of speed and/or redundancy attributes of your data volume.

Change Your Reality

OWC Accelsior 4M2 SSD showing fast lanes of traffic

Accelsior 4M2 offers performance gains in so many diverse ways that it will literally change the paradigm for storage applications. For 4K and 8K video and VR environments it allows streaming and editing without a glitch, plus faster previews, renders, and processing in VFX programs. Keep page scenery and textures looking sharp and flowing uninterrupted in virtual reality environments and ensure augmented reality visualizations look life-like. Hard core gamers can change game levels seamlessly and play flight/driving/MMO games with continuously changing scenery and heavily personal preference modded games without micro-stuttering.


  • Supercharges Macs and PCs – ideal for Mac Pro 2019, Mac Pro 2012 or 2010, and PC towers
  • Work faster – over 6,000MB/s real-world speed in RAID 0
  • OWC Aura P12 powered solutions – advanced PCIe 3.0 M.2 NVMe Technology
  • Store more – store up to 8TB of critical footage, images, files and games
  • Bootable – start working in seconds
  • Slot-powered – no extra power cables needed
  • Includes SoftRAID: robust software for TRIM, healthy monitoring and custom creation and management of advanced RAID sets
  • Deployment ready – pre-configured solutions undergo performance verification
  • Silent cooling – finned heat sink cover for fan-less operation
  • Highly versatile – installs into a full-height, half-length x8 or x16 PCIe 3.0 or 2.0
  • Plug and Play – no drivers needed
  • Worry-free – up to 5-year OWC Limited Warranty

Pricing & Availability

The Accelsior 4M2 SSD is available now for pre-order at in capacities from 0GB (add your own drives) starting at $249.99, or from 1TB to 8TB starting at $519.99. It will begin shipping the week of December 30th.

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  • Hi,

    I would like to know if this device will work in a Sonnet Echo Exp I that gave a 8x Pcie mechanical slot and a thunderbolt connection to the Mac ?

    That would be interesting because in this case, it will work on a MacPeo 2013 and would avoid me to buy a MacPro 2019

    Do you have alternative Pcie extension to suggest ?


    • I don’t believe this has been tested with a Sonnet Echo Express, but I will submit a request with Product Development to see if they can do it for you. I’ll post any updates here!

  • Love the fanless engineering but still trying to find detailed performance data for this product. I’m not finding anything here or elsewhere, neither for the current model nor pre-7,1 model, that shows how it performs across a broad variety of use cases. In particular, the 6GB/s number isn’t clear to what extent it maintains that throughput over large sustained writes (where most NVMe drives exhaust their SLC cache at some point and exhibit a performance knee).

  • I received mine recently. I have a 2012 Mac Pro and a Radeon 580 double slot card in it. Sadly the 4M2 has 2 metallic cubes on the bottom which prevent it from being mounted in the second 16x slot. The only way to do it is put the 4M2 in the first 16x slot, graphics card in the second 16x slot, which then blocks one of the 4x ones.

    Maybe I missed something but it would have been nice to have known this before ordering.

    • Hi Al, thanks for reaching out to us.

      I brought this to the attention of our Product Development team. They said that the tests performed in our labs were successful, but we are now receiving reports that there are slight variances between machines and graphics cards that make the fit more difficult. We have just released some documentation that details this further:

      If you haven’t done so already, I would recommend calling Customer Service to see what they can do for you.

      • I’ve ordered a single-slot graphics card. However, the product marketing should really have a clearer warning about this. I’m sure a large number ofpotential purchasers have double-slot cards in their machines.
        Also, the text on ‘no drivers required’ is misleading, I’ve now found out I need to reformat one blade as a boot drive and create a new RAID array for the remaining 3 blades. I’ve downloaded the software for this but a video on how to set it up would be helpful (maybe it’s dead easy but the idea of messing with RAIDs without previous experience is a little unsettling).

        • Thanks for the feedback, Al – I have passed it along!

          In regards to the softRAID download, one of our engineers mentioned to me that certain tasks, including reformatting, can be done with DiskUtility. We’ll look at updating the page to say something to that effect.

  • Will this be offered in single JBOD drive configurations, for those who would prefer not to have the capacity spread across four? (This was an unwelcome surprise when I recently received a 1TB 4M2 card.) As I will be returning the one I received, do you have any ETA for either a single-drive 1TB card, or the 0TB version?

    • Hi Jeff!

      1) You can destroy the RAID set and run the drives in JBOD on any of these models, we just pre-configure them in RAID 0.
      2) The 4TB model will have four 1TB drives on it.
      3) The card will ultimately be offered in 0TB.

      You can also check out the Accelsior 4M2 page at for additional information.

      I hope this answers your questions!

      • OK, part of the issue I had with the 4M2 card I received, is that nowhere, including this blog (prior to your last reply), did OWC state that these come pre-populated with four NVMe drives in a RAID-0 configuration. The current page is somewhat better, thank you, but still easy to miss important considerations.

        I don’t currently need four 1TB drives, so as of now, OWC has no option that is suitable for my needs. That, unfortunately, makes the x16 Highpoint adapter the more cost-competitive four-slot option for our 2012 MacPro (or the 2-slot x8 IO Crest).

  • Nice, but those blades are 2 TB. Please, bring also 4 TB and 8 TB blades (like Micron, Toshiba, Apple, etc) in both external (USB 3 & Thunderbolt 3), for a total of 4, 8, 16 & 32 TB.

  • Beautiful product and very timely !

    Am I correct in thinking that because of the T2 chip it will not be possible to use this device as the boot drive on the new 2019 Mac Pro ?

      • Thanks for the reply.

        The reason why I asked is that I was intending to order a Mac Pro with the optional 8TB SSD. However, as the OWC card is both faster and less expensive, I thought a better option would be to install the OWC card, unplug the Apple SSD and boot from the OWC card, if that is possible.

      • Thanks for the tip about the T2 chip.

        Can macOS Catalina boot from a RAID drive, which you would be doing if you used the Accelsior 4M2 as your boot drive ?

        • Booting from any RAID drive will be an issue, so it’s always advised to use an internal drive.

          I passed this by one of our OWC engineers, and his response was, “If you want to use an Accelsior 4M2, or similar product like a ThunderBlade, as a boot drive, you would have back up any necessary data on the volume, use SoftRAID to delete the RAID, zero one of the disks (first and last 100 should be OK), format the blank disk with Disk Utility, and install macOS.”

          • Do I understand this to mean that you could use one of the four blades as the boot volume but not all four RAID’ed together ?

          • I think I will order the new tower with 1TB boot drive from apple and configure added storage onto that, either pcie blades and/or sata storage in that drive caddy you can buy.