Bare Feats

REVIEW: Sonnet Technologies M.2 4x4 PCIe Card for Mac Pro

The best way to create a fast storage array for your Mac Pro is to install an M.2 PCIe board populated by multiple M.2 PCIe-based flash modules in a striped array. Perfect example: The new Sonnet M.2 4x4 PCIe Card. Apple includes it in a list of ‘blessed’ PCIe boards for the 2019 Mac Pro, but it also works in the 2010 - 2012 Mac Pro.

…because of the 2010 Mac Pro’s PCIe bus speed limit, we observed that three striped 970 PRO modules transferred as fast as four. So that opens the door to using the fourth M.2 flash module as a separate volume. For example, you could have a single module as a boot drive running macOS Mojave and the remaining three striped (RAID 0) modules serving as a very fast read/write working project volume and/or scratch volume.

Read Full Review

9 to 5 Mac

Sonnet's M.2 4x4 PCIe Card Brings Absolutely Ridiculous SSD Speeds to Mac Pro

If you’re looking for the fastest SSD available for the Mac Pro, then this may be the solution for you. When paired with the right SSDs, the Sonnet M.2 4×4 PCIe Card produces speeds of the bonkers variety.

During benchmark tests with the Blackmagic Disk Speed Test utility, I was getting write speeds in that easily surpassed 6,000 MB/s, and read speeds that eclipsed 7000 MB/s.

For comparison’s sake, Apple’s fastest 8 TB SSD produces speeds “only” up to 3400 MB/s, so this setup is capable of running circles around the Mac Pro’s fastest built-in SSD for less money. Watch our hands-on video review for the details.

Read Full Review

Technical Specifications

Mac, Windows, and Linux Logos


Mac Compatibility

  • Mac Pro 5,1(4) (Mid 2010 & Mid 2012) with available full-length x16 PCIe slot
  • Mac Pro 7,1 (2019) – Use x16 PCIe slot (slot 3, 4, or 5) for full performance
  • macOS 10.13.6+(5)
  • macOS Big Sur compatible

Windows Compatibility

  • Computer with available full-length, full-height x16 PCIe slot (PCIe bifurcation not required)
  • Windows 11, 10

Linux Compatibility

  • Computer with available full-length, full-height x16 PCIe slot (PCIe bifurcation not required)
  • Linux Kernel 5.0+

Thunderbolt Compatibility(6)

  • Mac (Intel® or M1) computer via a Thunderbolt PCIe card expansion system with available full-length x16 PCIe slot
  • Windows computer via a Thunderbolt PCIe card expansion system with available full-length x16 PCIe slot
  • Linux computer via a Thunderbolt PCIe card expansion system with available full-length x16 PCIe slot


Part Number

  • FUS-SSD-4X4-E3S


  • 2-year

Form Factor

  • Full-length, full-height computer card

Internal Connectors

  • Four M-keyed (NVMe) M.2 sockets

SSDs Supported(1)

  • Single-sided and double-sided(2) M.2 2280 NVMe PCIe SSDs

Supported SSDs Compatibility Chart

PDF Icon

Boot Suppport

  • macOS
  • Only from a single SSD (not RAIDed)
  • Mac Pro 5,1 or Mac Pro 7,1
  • Any Thunderbolt Mac
  • Windows, Linux
  • No

RAID Support

  • macOS(7), Windows, Linux
  • RAID 0, 1, or 5 (Stripe, Mirror, or Parity)

NVME Support

  • Yes

S.M.A.R.T. Status Data Reporting Support

  • Yes

RoHS Compliant

  • Yes

Package Contents

  • Sonnet M.2 4x4 PCIe Card
  • Thermal transfer pads
  • SSD mounting screws
  • Documentation

Support Links

Support Knowledge Base

Drivers, Documentation, FAQs

Product Manual

PDF Icon

Technical Notes

  • You may install fewer than four SSDs now and add more later without needing to reformat existing ones. Only 2280 (80mm—the most common length) length M.2 SSDs are supported. M.2 SSDs longer or shorter than 80mm don’t fit.
  • Double-sided SSDs (SSDs with components on both sides) supported on FUS-SSD-4X4-E3S with serial number A01298060001200+. FUS-SSD-4X4-E3S with lower serial numbers require a thermal pad modification to support double-sided SSDs.
  • This product’s performance will vary based on the type and number of SSDs used, the CPU speed, and the PCIe architecture.
  • See this Mac Pro installation video.
  • macOS 10.14.6+ supports both 512 and 4k block size SSDs, but macOS 10.13.6 supports only 4k block size SSDs. SSDs 1TB or larger are shipped from the factory programmed with a 4k block size. If you have smaller SSDs that are programmed with 512 block size, and you need to be compatible with macOS 10.13.6, you may need to reprogram your SSDs to a 4k block size. See this tech note for more details.
  • Performance in a Thunderbolt 3 PCIe expansion system limited by maximum Thunderbolt 3 PCIe bandwidth of 2,750 MB/s. PCIe bandwidth of Thunderbolt 2 is about half of Thunderbolt 3.
  • RAID 5 support under macOS requires third-party software such as SoftRAID, sold separately.

Sonnet M.2 4x4 PCIe Card (Silent)