Posted on Friday, March 1, 2024

In Review: A Look at OWC's Dual Slot SDXC USC-II USB-C Card Reader and ATLAS ULTRA 256GB SD Card

By Mark Foley, Technology Editor, ProductionHUB

You know the feeling — you're on a shoot or edit and you notice you're running out of SD cards, and even worse, running out of time. Admittedly, we've all experienced this at some point. So, what are you supposed to do in these situations? I found a really simple solution to those problems in a recent review I conducted testing out the Dual Slot SDXC USC-II USB-C Card Reader and OWC ATLAS ULTRA 256GB SD Card from OWC, also known as Other World Computing. Needless to say, I came away quite impressed from the experience, but first let's dive into some physical observations.

The Dual Slot SDXC USC-II USB-C Card Reader came in a nice compact and easy to deal with size and matched up color scheme wise visually with my oldish MacBook. Not really a big deal but with my Mac Mini it just looks better on my desk. The reader weighs practically nothing coming in at an amazing 4.9 ounces.

Additionally, the Dual Slot SDXC USC-II USB-C Card Reader sports a very smart space on the back to hold the built in USB cable. It is a nice design touch for everyone that is forever trying to deal with cable spaghetti on the road, and also guarantees you won’t be stuck when you manage to leave all your cables at home on the plane. Not that I've ever done that, of course.

End user, Becca Funish, had this to say about the OWC for the Dual SD Card Reader. “I love it! The speed is amazing. It’s great being able to offload two cards simultaneously since my camera has two slots for recording.” Becca also added this thought: “Definitely a huge time saver in my workflow!”

Even through my MacBook only had an older USB port, I was still able to connect the OWC reader via the extra cable and the additional USB II port provided on the back of the reader. The reader also had a lockout that allows the user the option so you can prevent accidentally overwriting/deleting your precious data or reformatting your SD card in either slot with that lifesaving Write Protection switch so you don’t zombie out and accidently nuke your footage or expensive graphics package during that dreaded 2AM overnight edit session. When you want a peace of mind update on each slot's power and activity status, separate LEDs also keep you clearly informed.

Taking a Look at the Tech Specs for the OWC Dual Slot SDXC USC-II USB-C Card Reader

As they say in my native Boston, the reader is WICKED fast. I have never up to this point been able to move data in the form of stills and videos around so quickly. This includes the tremendous amount of 4k video I was using as my test case scenario. Dare I say seamless transfers? I also loved the form factor that the reader was a dual slot setup. Moving my stuff around was quick and easy.

I also wanted to share some of the technical specifications that makes the OWC Dual Slot SDXC USC-II USB-C Card Reader and the OWC ATLAS ULTRA 256GB SD Card such a pleasure to use.

I Feel the Need for Speed and More

Data transfer speeds can reach over 300 MB/s per slot, for a total bandwidth of 600 MB/s, P Power for the reader comes from your computer from the computers USB Ingest data 2X faster with the Atlas Dual SD Reader and start working with your content faster. This compact reader "eats up" data at real-world tested speeds of over 300 MB/s on two cards simultaneously for a combined bandwidth of over 600 MB/s. Transfer thousands of photos totaling 250GB in less than seven minutes vs over 14 minutes with a single slot UHS-II reader.

No worries if you accidentally connect that cable from a power supply to the USB-C port, as the Atlas Dual CF Express and SD Reader has built-in protection to prevent overpowering.

Here are some other features that are worth looking at when considering the OWC Dual Slot SDXC USC-II USB-C Card Reader.

Innergize Your Workflow with Highest Performance and Reliability OWC Innergize is a OWC custom-designed app is a complete health, performance, and field upgrade management tool when using OWC Atlas memory cards with OWC Atlas readers and reader equipped products or when using select OWC portable flash SSDs.

Over time and use cycles, flash memory does wear out. Innergize verifies and reports the percentage of use life remaining.

Sanitize: Writes, Deletes, and Formatting

These actions take their toll on memory cards and portable drives. Innergize cleans and restores the flash memory performance of OWC memory cards and portable drives so you can get the best results on every use.

Field Upgrade When new cameras or firmware updates to existing cameras are introduced, they may not work properly with flash memory cards and drives. Innergize gives OWC memory card and portable drive users the ability to upgrade their firmware in the field for full compatibility, additional performance enhancements, and bug fixes for optimal reliability.

Please note that to obtain maximum reader performance, Apple Mac M2, M1 Pro, and M1 Max machine users should update to macOS 13.3 or later. Apple Mac M1 users will experience lower than stated reader performance due to M1 data transfer performance.

Windows Compatibility

Windows 10 (32-/64-bit) Windows 11 Windows Server 2016 Mobile OS Compatibility

iPadOS 13 iPadOS 14 iPadOS 15 iPadOS 16 Android 11.x Android 12.x Android 13.x Other OS Compatibility


Last but not least, I normally don’t wax poetic about a SD card reader or SD Card in general but here is the exception that I had to include. The OWC ATLAS ULTRA SD 256GB was a solid add on to the Atlas card reader experience. Touted as a high-performance, with the highest quality memory card for advanced photography and video recording at maximum camera settings. The card did not disappoint.

Additional Specs Below:

  • Up to 250MB/s Write Speed
  • Up to 300MB/s Read Speed
  • Guaranteed minimum 90MB/s Sustained Write Speed
  • Ultra-speed: up to 250MB/s write and 300MB/s read real-world speeds for the most advanced use cases of professional content creators including high burst image sequence RAW photography and high bitrate 4K and 6K video recording1
  • Dependable: delivers 90MB/s minimum sustained write speed
  • Proven: extended time tested in highest settings of high-end cameras
  • Tough: bend/shock/X-ray resistant and IP67 dust-proof and waterproof
  • Supportive: fully compatible with a wide variety of DSLR and mirrorless cameras
  • Flexible: backwards compatible with previous generation of SD devices and readers
  • 3 Year OWC Limited Warranty

Closing Thoughts

The other SD card I was using along with the Atlas Ultra was one of my old reliable SanDisk cards. It loaded right up and seemed to move the data just fine. I'm sure you may have as many SD cards laying around like me and I do plan to use them and archive all of them. The Dual SD Card Reader from OWC will help move that project along at a much better clip than I first thought possible.

OWC also makes a version of the reader that has one SD slot and one CF Express slot for those professionals that need or want to use both. I don’t think SD Cards are going away any time soon and for the price (79.99 list), the OWC Dual SD reader would be a wise investment for shooters and photographers that need real speed and portability.

Lastly, it should be noted that when I had a few questions about the card reader I got on a call in with the OWC technical staff. They were quite friendly and knowledgable, quick to ask the right questions, give me some very clear directions, and I was merrily on my way. It was a breath of fresh air to get that level of customer support. They have my vote of confidence.