Lexar Professional CFexpress Type-B Card Review (256GB) – Much Anticipated Media Storage Speed

I am somewhat of a camera buff.  I love photography and I carry a Canon 5D Mk IV, that even I will admit is much to far ahead of my skill set.  My wife.  Well, she used to take incredible pleasure in reminding me how many all inclusive vacations this camera cost.  That was until I started shooting family weddings.

I am also a storage guy.  This is a dangerous thing when it comes to media.  I understand first hand that the camera industry has failed media professionals through substandard storage in the worlds best equipment for some years.  For example, the image buffer.  Anyone who has ever shot a wedding, sports or wildlife has lost pictures because of a filled buffer, where companies could have upgraded this through flash years ago.  It is simply the speed of data storage.

The buffer holds your image data until the camera can get it onto the storage card.  Up until recently, media storage has been limited, for the most part, to speeds of 100MB/s.  Sony changed that with XQD cards for Nikon Z6 and Z7 cameras that reached 400MB/s. Today, our report is on the latest and greatest Lexar CFexpress Type-B Card which pushed in-camera speeds through the roof to 1750MB/s.

We are not quite sure yet whether CFexpress Type-B will be abbreviated to CFX-B or CFx.  Both are used.  For now, we are aware that the Canon CF500 MkII will accommodate the CFx card, along with the Nikon Z6 and Z7 with software upgrades.  It is also backward compatible to any XQD camera. The Lexar Professional CFexpress Type-B card is a PCIe 3.0 card that uses the latest in NVMe 1.3 protocol.  Have a look.


The difficulty with CFexpress Type-B is that it will reach speeds of 1750MB/s read and 1000MB/s write so we had to find a way to test it in a PCIe 3.0 x2 device.  Lexar created this adapter for us.  It is the only that we know of in existence right now and can be used to test any CFexpress card.


The Lexar Professional CFexpress Type-B card is available in capacities of 64-512GB and has a lifetime limited warranty.  Amazon pricing is $349.99 for the 256GB version we are testing today, along with $179.99 for the 128GB capacity.  We are not seeing availability of the 64GB and 512GB right now but check this link for updates and pricing.



ATTO Disk Benchmark is perhaps one of the oldest benchmarks going and is definitely the main staple for manufacturer performance specifications. ATTO uses RAW or compressible data and, for our benchmarks, we use a set length of 256mb and test both the read and write performance of various transfer sizes ranging from 0.5 to 8192kb. Manufacturers prefer this method of testing as it deals with raw (compressible) data rather than random (includes incompressible data) which, although more realistic, results in lower performance results.


Our initial ATTO Disk Benchmark was a great start for the Lexar Professional CFx Card, showing an excellent progression with data sizes and exceeding listed specs.  Lets check out a few more benchmarks on the next page…


  1. blank

    At the totally excessive prices for CFexpress, this should be at least 3D XPoint SLC memory. Connected to four PCIe V4.0 lanes (64GBit/s). According to the 4K values, this is TLC memory at best. The Sustained Sequential Write Performance at 128KB would interest me very much.

  2. blank

    Thanks for this benchmark, seems to become the next standard in photography. Are any additional information available about the adapter(s)? This would be a nice one for dev purposes.

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