Sonnet's Fusion Flex J3i Mount Lets You Add Up to Three Internal Drives to Your Mac Pro

Sonnet today announced the upcoming launch of its Fusion Flex J3i internal drive mount for the 2019 Mac Pro, which lets users add up to three SATA storage drives to their machines.

sonnet fusion flex installed
Sonnet isn't the only company to launch an internal drive mount for the new ‌Mac Pro‌, and Apple itself sells Promise's Pegasus J2i system that lets you add two drives, but Sonnet says it's the first to let users add three drives right inside the ‌Mac Pro‌ and connected directly via SATA.


The Fusion Flex J3i offers two slots that can accept either 3.5-inch hard disk drives or 2.5-inch SSDs, and a third slot that accepts a 2.5-inch SSD, allowing for a total of 36TB of additional internal storage.

Storage installed via the Fusion Flex J3i won't be as fast as the main NVMe SSDs at the heart of the ‌Mac Pro‌ or PCIe-based storage upgrades, especially if you're using traditional hard disk drives, but if you're a user who wants to prioritize storage space and simplicity over drive speed, Sonnet's Fusion Flex J3i might be worth checking out.

sonnet fusion flex kit
The Fusion Flex J3i includes the mount, required power/data cable assemblies, and mounting brackets to fit 2.5-inch drives into the 3.5-inch drive slots, but the drives themselves are sold separately. It will be priced at $199.99 and launches on June 15.

Related Roundup: Mac Pro
Tag: Sonnet
Buyer's Guide: Mac Pro (Neutral)
Related Forum: Mac Pro

Popular Stories

Generic iOS 18 Feature Real Mock

iOS 18 Available Now With These 8 New Features For Your iPhone

Sunday September 15, 2024 10:09 am PDT by
Following over three months of beta testing, iOS 18 was finally widely released to the public on Monday, September 16. The update is available in the Settings app under General → Software Update on the iPhone XS and newer. Below, we have highlighted eight key new features included in iOS 18, and Apple shared a complete list of new features and changes last week. Note that Apple...
iOS 18 Public Beta Thumb 1

Here's When iOS 18 Rolls Out Today in Every Time Zone

Monday September 16, 2024 3:56 am PDT by
It's that time of year again. Apple is about to release iOS 18, which promises to bring a range of new features and improvements to iPhones worldwide. It's Apple's biggest software update of the year, and the company is expected to release it sometime today – Monday, September 16. Based on past releases, the update is likely to drop at around 10:00 a.m. Pacific Time/1:00 p.m. Eastern...
M4 Mac mini Black Ortho Cooler

Apple Leaks New Mac Mini With 5 USB-C Ports

Monday September 16, 2024 11:40 am PDT by
Apple has seemingly leaked the rumored next-generation Mac mini with five USB-C ports, according to a code change within Apple software that was discovered today by MacRumors contributor Aaron Perris. The code refers to an unreleased Mac mini model with an Apple silicon chip and five ports, which lines up with a previous report from Bloomberg's Mark Gurman that said the next Mac mini will be ...
iOS 18 Apple Account Name Feature 2

RIP, Apple ID

Tuesday September 17, 2024 3:18 pm PDT by
The "Apple ID" era is officially over. The transition from "Apple ID" to "Apple Account" went from a rumor to an official announcement to something that has now been fully completed. As of this week, the account.apple.com website is fully updated with Apple Account branding. "Apple ID is now Apple Account," the page says. "You can still sign in with the same email address or phone...
apple silicon mac lineup wwdc 2022 feature purple

M4 Macs, New iPad Mini, and iPad 11 Expected at Upcoming Apple Event

Sunday September 15, 2024 5:29 am PDT by
Apple will likely hold another event in October this year to announce new Macs and iPads. If so, it would be the fourth time in the last five years that Apple has held an event in October. Last year, Apple held a virtual event on Monday, October 30 to announce new MacBook Pro and iMac models with the M3 series of chips. In his Power On newsletter today, Bloomberg's Mark Gurman reiterated...
16 pro

iPhone 16 Pro Demand Has Been Lower Than Expected, Analyst Says

Sunday September 15, 2024 3:58 pm PDT by
Apple analyst Ming-Chi Kuo today said demand for the iPhone 16 Pro and iPhone 16 Pro Max has been "lower than expected" since the devices became available to pre-order in the U.S. and dozens of other countries on Friday. Kuo said his data is based on a "supply chain survey" and shipping estimates listed on Apple's online store. Kuo estimated that sales of all four iPhone 16 models reached...

Top Rated Comments

Rychiar Avatar
56 months ago
wait these things don't allow more than one in the first place??
Score: 8 Votes (Like | Disagree)
WildCowboy Avatar
56 months ago

wait these things don't allow more than one in the first place??
The stock storage is either one or two Apple-proprietary storage modules tied to the machine's T2 chip. You can go up to 8TB total with those.

Beyond that, it's either PCIe-based storage, internal SATA like this, or external options.
Score: 8 Votes (Like | Disagree)
Darth Tulhu Avatar
56 months ago
There was a time when I would drool over stuff like this (I still kinda do).

My days of popping the hood are behind me (even though I've been keeping my 2011 17", and 2012 iMac and 15" alive for the last couple of years with those skills).

I'm amazed that we live in an age where I can ACTUALLY replace my hardware with an iPad!

I no longer need the power this machine offers, even if I think it's cool that it can provide it.
Score: 8 Votes (Like | Disagree)
Stang Avatar
56 months ago
$200 for a piece of plastic and 3 sata cables? Yikes.
Score: 8 Votes (Like | Disagree)
SSDGUY Avatar
56 months ago

wait these things don't allow more than one in the first place??
I believe they can take two drives without an expansion mod.
Score: 5 Votes (Like | Disagree)
theluggage Avatar
56 months ago
$200 for a mounting bracket and 2 slightly-customised SATA cables that should have been included with the Mac in the first place...

To be fair, the third cable is a USB3-to-SATA cable which might set you back as much as $7!

Sheesh. I've bought entire PC cases that cost less than $200 and they don't charge extra for the flippin' drive brackets. ...and that's premium Fractal Design/Silverstone stuff that you can compare with Apple and keep a straight face, although the Mac Pro blows right past "premium" and into "over-engineered to the point of parody"...

OK, I know all the big IT firms will charge you $50 for a cable tie if they think you're ordering with a corporate credit card and not watching the price, but that doesn't make it right - and they're usually doing it to compensate for under-bidding on support contracts.


Super weird how the third caddy connects via and internal USB3 cable, rather than SATA like the other two.
...probably because there are only 2 SATA connectors (plus a USB-3) on the Mac Pro mainboard...?
Score: 5 Votes (Like | Disagree)