Lexar 128 GB CFexpress Memory Card

With the release of fast NVMe PCIe-based storage on our computers, we have gotten used to their incredible transfer speeds. Camera manufacturers have been catching up with the latest technology, and thanks to their efforts, we now have cameras with XQD and CFexpress memory card slots as well. As an owner of both Nikon Z6 and Z7 mirrorless cameras, I have been heavily using XQD cards with these cameras. Ever since Nikon delivered a firmware update to make the cameras compatible with CFexpress, I really wanted to find out if I could take advantage of these faster cards. In addition, I wanted to see if faster CFexpress cards are going to make any difference in buffer capacity and the speed of image transfer when compared to XQD cards. After I obtained the Lexar 128 GB Professional CFexpress memory card, I decided to test it thoroughly on my computer as well as my Nikon Z cameras to see how it performs.

Overview and Build Quality

The Lexar 128 GB CFexpress memory card is a “Type B” memory card based on the CFexpress 2.0 version and PCIe 3.0 x4 bus. Per its specifications, the card is capable of 1750 MB/sec read and 1000 MB/sec write speeds, which is insane! Compare that to the fastest XQD memory cards available today that max out at 440 MB/sec read and 400 MB/sec write speeds and you will see why CFexpress is so much better technically.

The build quality of the Lexar 128 GB CFexpress card is excellent. The memory card features an aluminum chassis with some labels (including a label that says “Lexar, an affiliate of Longsys, a Chinese company”), while the top plastic cover has the main label that shows the memory card capacity, CFexpress Type B logo, 1750 MB/sec read speed, as well as “Lexar Professional” logo (exactly as shown in the image above). The serial number of the memory card is displayed on the front side.

Lexar 128 GB CFexpress Card Specifications

Below are the specifications of the card:

Compatibility

It is important to note that CFexpress cards are very new and you should absolutely make sure that it is compatible with the device you are intending to use it on. Since there are multiple CFexpress types (A, B and C), you should first make sure that it is the correct type on both ends (the memory card itself, as well as the device / reader). Second, you should make sure that you obtain a CFexpress memory card reader that is capable of reading CFexpress cards. Initially, I had no idea that my Sony XQD card reader would not be able to read CFexpress cards, and it was painful to find out that Lexar’s CFexpress card reader (which I will review next) does not read XQD cards either.

This is a pretty big problem for those who use both XQD and CFexpress cards – unless you specifically purchase a memory card reader that can read both XQD and CFexpress cards, you will be stuck with having to use multiple readers. And as it turns out, most manufacturers have not been able to figure out how to read both XQD and CFexpress memory cards! The only memory card reader that seems to work, more or less reliably with both, is the Sony MRW-G1, which is out of stock everywhere I looked. Even then, I would hesitate to use brands other than Sony on that reader, since the product page for the Lexar card reviewed here says “this card may not be compatible with Sony CFexpress devices” on B&H product page. Sucks, but it seems like there might be cross-brand compatibility issues with CFexpress memory cards and readers. Even Nikon’s initial CFexpress firmware for Z6 / Z7 was not compatible with CFexpress cards from ProGrade and Lexar, so we had to wait until firmware 3.0 to get proper support.

Unfortunately, this is all pretty new technology, so it is likely going to take a few years until we get reliable CFexpress cards and readers that work with most devices out there. So keep all this in mind if you decide to move up to CFexpress – there might be hidden costs and frustrations along the way.

Performance

So, how does the Lexar 128 GB CFexpress card perform in terms of transfer speeds? Due to my inability to get the Sony MRW-G1 card reader, I had to use Lexar’s very own CFexpress USB 3.1 reader, which sports a 10 GB/s USB 3.1 Gen 2 Type-C interface (but comes with a USB Type-C to USB Type-B cable). I measured the performance of the card on both PC and Mac. Here are the PC results, based on CrystalDiskMark 1 GB benchmark:

As you can see, I was able to get roughly 835 MB/sec read and 811 MB/sec write speeds using this card and card reader. Pretty far from the advertised potential speeds. I had the card reader connected directly to my PC motherboard with a USB 3.1 port, so there were no other bottlenecks that could limit the speed. I performed several tests, and each time I was not able to pass 850 MB/sec read speed.

I then performed another test, this time with a 4 GB file. Here is the result of the benchmark:

Once again, the sequential speed maxed out at 845 MB/sec read and 807 MB/sec write speed. I know that 1750 MB/sec is a theoretical maximum, but still, I was hoping to get at least over 1 GB/sec read speeds with this card.

Thinking that perhaps something is wrong with my PC setup, I moved to my iMac Pro. I connected the memory card directly into one of the Thunderbolt 3 connections on the back of the iMac Pro and ran a few tests, including Blackmagicdesign’s Disk Speed Test. Here are the results:

Again, I topped out at about the same speeds – 859 MB/sec read and 872 MB/sec write. So my PC is just fine – the issue is either with the card itself, or with the memory card reader that cannot read at faster speeds. For now, I am going to rate the card a bit low for its performance, but I will be testing it with the above-mentioned Sony reader once I am able to purchase it to see if I can drive the card further. I will update the ratings accordingly.

Still, even with these speeds, the difference in CFexpress and XQD cards is very significant. Take a look at the benchmark results from my Sony 64 GB XQD memory card:

That’s a crazy 4x read and 6.6x write difference between these two cards! The big question is, does the new CFexpress card make any difference when shooting with the Nikon Z6 or Z7?

I tested out my Nikon Z7 with the both cards, and here are the results when shooting with 14-bit losslessly compressed images at maximum FPS:

• Buffer Capacity with XQD card: 2.5 seconds
• Buffer Clearing with XQD card: 5.2 seconds
• Buffer Capacity with CFexpress card: 2.5 seconds
• Buffer Clearing with CFexpress card: 5.1 seconds

Basically, there is no performance difference between XQD and CFexpress cards on the Nikon Z7. My guess is that the Nikon Z6 / Z7 cameras have an older XQD / CFexpress memory card slot that is limited to PCIe 2.0 speeds for both card types. Yes, it can read CFexpress cards, but it cannot take advantage of them. So if you have been thinking about moving up to CFexpress in hopes of getting better buffer capacity, you will be sorely disappointed. We will need to wait for the next generation Nikon mirrorless cameras that might have PCIe 3.0 CFexpress card slots that will actually take advantage of faster card speeds.

Summary

The Lexar 128 GB CFexpress memory card is a well-made card with excellent build quality. While it seems to be a card capable of extremely fast speeds, unfortunately, I was not able to achieve these speeds with Lexar’s CFexpress USB 3.1 card reader. Still, even with lower read and write speeds, being able to transfer files at over 800 MB/sec is very impressive, especially when compared to XQD cards.

The biggest issue with CFexpress cards today is compatibility. As I have explained earlier, you will need to make sure that you get the right type of card, the right type of memory card reader, as well as ensure that you have a fast-enough USB or Thunderbolt connection on your computer in order to be able to take full advantage of these cards. In addition, if you are using a mix of XQD and CFexpress cards, be prepared to face issues with memory card readers, as they do not seem to like both card types.

If you do not own any XQD memory cards today, then, by all means, go for CFexpress. These memory cards are priced about the same as XQD memory cards, and it just does not make any sense to invest in older technology when your devices support CFexpress. However, if you already own XQD memory cards, then you will need to see how you can address the memory card reader problem. I will personally wait until I can find a memory card reader that reads both without issues, because I do not want to deal with several card readers, especially when traveling. I hope the Sony card reader I mentioned earlier is going to be available soon so that I can test it out…

If you already own the Sony MRW-G1 reader and use it with both XQD and CFexpress cards without issues, please let me know in the comments section below. Also, please let me know if you are able to get speeds above 850 MB/sec on that reader. I would love to hear your feedback, thank you!

Where to Buy

If you would like to support our efforts, please consider buying from our trusted partner B&H Photo Video:

• Lexar 64 GB Professional CFexpress Memory Card
• Lexar 128 GB Professional CFexpress Memory Card
• Lexar 256 GB Professional CFexpress Memory Card
• Lexar 512 GB Professional CFexpress Memory Card