OWC Gemini review: External storage and some extra ports for your Mac


AppleInsider is supported by its audience and is eligible to earn an Amazon Associate and Affiliate Partner commission on qualifying purchases. These affiliate partnerships do not influence our editorial content.

The OWC Gemini is a docking station that not only offers a few extra port options for your Thunderbolt 3-equipped Mac, but also local storage.

There are a few “problems” we hear about when it comes to Apple’s modern Mac lineup. More connectivity options than those offered by Apple have always been one, which can be solved with a docking station or a hub. The other common complaint issue is storage. The main solution to this is external boxes, either networked or locally available.

For people who need both, the OWC Gemini can be a decent package help solve both problems at the same time.

The OWC Gemini is a Thunderbolt 3 docking station that provides expanded connectivity to a connected Mac. At the same time, the case can hold a pair of SATA HDDs or SSDs, providing extended storage capacity for the user.

Key specs

  • 5.8 inches by 9.4 inches by 8.5 inches.
  • 3.53 pounds.
  • 2 Thunderbolt 3 ports.
  • 2 USB 3.2 Gen 1 Type-A ports.
  • Display Port.
  • Gigabit Ethernet.
  • SD card slot.
  • Holds 2 x 2.5 or 3.5 inch SATA hard drives or SSDs.
  • Holds up to 32TB capacity.
  • 773 MB/s claimed transfer speeds.

OWC Gemini – Physical Dimensions

The Gemini is indescribable, consisting of a black aluminum casing with vent holes, status indicators and an SD card slot on the front. An exhaust fan and most of the main connectivity are on the back.

It’s not really intended to be a portable docking station, with its empty weight of 3.53 pounds making it less than ideal for portable computing. That said, it’s also long and tall enough for a docking station or hard drive enclosure, at 9.4-inches long, 5.8-inches high, and 3.3-inches wide.

Cooling is provided both by the heat dissipation properties of the case itself and by the 60mm fan on the back, which operates at up to 3000 rpm.

The Gemini will likely be louder than an Apple Silicon computer it’s plugged into. We had a baseline of 36 dBa of ambient noise measured with a Kanomax Model 4431 audiometer, with the test equipment on the desk at hand height, about three feet away.

When chattering under load, the Gemini with two hard drives reached 44 dBa. With two SSDs, it ran at 40 dBA. For reference, the M1 Ultra Mac Studio in standby achieved 39 dBa in standby and 42 dBa under load, with the 2018 MacBook Pro Intel i9 in standby running at 40 dBa and 45 dBa under heavy load.

OWC Gemini – Ports, Connectivity and Power

The dock item is pretty straightforward, as it offers a pair of Thunderbolt 3 ports, one of which is used to connect to the host Mac. The other is used for daisy chaining with other Thunderbolt devices.

On the front is the SD 4.0 card reader, capable of reading UHS-II cards at around 270 megabytes per second according to our tests. On the back, the Thunderbolt 3 ports are accompanied by two 5Gbps USB 3.1 Gen 1 ports, as well as a DisplayPort 1.2 connection, Gigabit Ethernet and a lock slot.

You can use both DisplayPort and Thunderbolt to connect to monitors, capable of handling one 5K resolution display at 60Hz or up to two 4K displays at 60Hz. The Thunderbolt 3 connection can be used for a 5K resolution Thunderbolt 3 display, although this drops to 4K 60Hz with a USB-C display or adapter.

OWC adds that DisplayPort does not support DP++ and is not compatible with Apple Cinema displays that use a Mini DisplayPort connection. Even if such a display is connected using a DisplayPort to Mini DisplayPort adapter, it won’t work, which OWC says is due to a limitation of the chipset it uses.

While this seems like an ideal docking station for a storage-limited MacBook Pro, for example, it won’t be the one-cable solution that many would want.

There’s power delivery via Thunderbolt 3, but only up to 27 watts, which isn’t enough to properly charge a MacBook Pro while in use, for example. It’s just a little less than the 30W provided by the charger with a MacBook Air M1.

How much of a problem this is, varies. That’s fine for the MacBook Air, obviously. If you have a 2021 MacBook Pro MagSafe, you can use it for power without giving up another port. You’re not going to charge a MacBook Pro at any speed, or while in use, without using a separate power cable.

In addition to the 27 watts to the host, the dock provides 15W of power to the other Thunderbolt port and normal power to USB-A.

Compatibility with Thunderbolt 2 and Thunderbolt as well, when used with a certified adapter and cable. Connection speeds slow to 20Gbps for Thunderbolt 2, though you also lose laptop charging support.

OWC Gemini – Storage

Inside the OWC Gemini there’s room for a pair of 3.5-inch SATA hard drives, although you can also use 2.5-inch SSDs if you prefer. The docking station chassis slides out of the front of the case, allowing you to slide and screw a drive on either side of the center divider.

Although the drives can appear independently in macOS with the dock attached, you also have the option of using its three RAID modes. This is configured by a dial in the lower right corner of the rear face.

Strictly speaking, there are two RAID modes, RAID 0 offering speed but no redundancy through disk striping, while RAID 1 offers users data security through its disk mirroring.

Six screws allow the assembly to slide forward and two 3.5-inch bays provide space for storage

The third option is “Span mode”, which will show both drives as one large drive in macOS. However, while RAID configurations require you to have disks of the same model and capacity, Span mode can use disks of different capacities and sources.

Span mode is still an array, but one where data is written to disks sequentially. If one disk fills up, all data continues to be written to the remaining storage on the other disk.

With up to 36TB of capacity supported across both drives, OWC says the enclosure, properly specced, can deliver up to 773MB/s of “real world” performance with drives in RAID 0. As billed, c is certainly enough access. speed for high-bandwidth users, such as video editors, to use in conjunction with the Mac’s built-in storage.

In our tests, we saw around 265 megabytes per second reading and writing to the hard drives. We also got 725 megabytes per second read speed and 700 megabytes per second when writing to a pair of 1TB SATA SSDs installed.

OWC Gemini – Pricing, empty and loaded

OWC offers the Gemini in a number of configurations, depending on how you want to acquire your desired configuration. For the case alone, you can buy it without any drive for $319.

There are options for OWC to include drives with the case, if you don’t want to worry about buying them. the cheapest model with storage costs $479 and includes two WD Blue 2TB 7200 rpm hard drives. For all other options, from $629 8TB variant and rising to $1,199 for the 36TB configurationOWC says it includes Toshiba hard drives, with “Enterprise” versions used from 16TB and up.

Should you buy the OWC Gemini?

We have mixed feelings about the OWC Gemini. We like the storage bays and ports it brings to the table.

But, like some other offerings, it just doesn’t provide enough host power for a MacBook Pro. And MacBook Pro owners are probably the most interested in this type of combo case.

It’s attractive and it works well. Speeds are good and the added connectivity is nice. It’s just a shame that if you want a one-cable solution for your MacBook Pro, you have to look elsewhere.

OWC miniStack STX Pros

  • Video, networking, and some USB-A ports in the same space an external hard drive takes up
  • Two internal 3.5-inch storage bays

OWC miniStack STX Disadvantages

  • Stronger than the host computer
  • Not enough reception power!

Where to buy the OWC Gemini


About Author

Comments are closed.