Best CFExpress Type-B Memory Cards – Real Benchmarks

The latest CFexpress Type-B memory cards are some of the fastest and most robust types of media you can use for your cameras today. But just how fast are they?

This guide will look at the different performance metrics of the various brands of memory cards.

Best CFexpress Memory Cards

Tested using a 2018 MBP with the Lexar CFexpress reader which does not take advantage of USB 3.2 2×2 20Gbps speeds supported by the Lexar reader, so these speeds would bottleneck down to 10Gbps speeds. The first two columns show what the rated speeds are, and the second two columns show the performance with the Lexar reader.

If a card performed poorly I also would check it in the Prograde Reader and Angelbird USB 3.2 2×2 Mk II reader just to make sure there were no issues with reader compatibility. Angelbird cards all have the latest 2022 firmware.

The software used was AJA System Test. Resolution: 5120×2700 5k Red / Test File Size: 4GB / Codec Type 16bit RGBA. Speeds are listed in Megabytes per second. For the High Heat test, I used the 64GB file size and ran the test multiple times until the card started to throttle.

Apple doesn’t seem to support USB 3.2 2×2 20Gbps speeds. The new M2 macs support USB 4, but I’m not sure if they will run 3.2 at 2×2 20Gbps or not. When I test in the Mac Mini it’s also significantly slower than the speeds I get from the MacBook Pro. The Mac Mini’s do not have a lot of bandwidth and generally get throttled pretty heavily as multiple components share the same bus.

Why some cards were so much slower?

You might look at this chart and see right away that some cards were significantly slower compared to their rated speeds. But actually, these cards still might be fine for you. Here is why.

These slower cards had very aggressive thermal throttling profiles which were more apparent with the large file size tests vs smaller file size tests.

I performed these tests using the AJA System Test using 4GB file sizes. The reason I chose 4GB is that this is about the buffer we see in some of the best cameras like the Sony A1 or A9. The Nikon Z9, also a great camera, only looks to have about a 2GB buffer. This makes sense, it’s using faster CFexpress Type-B cards instead of Type-A cards.

If I chose a larger size than 4GB in these benchmarks, it could cause the card to engage the thermal throttling more aggressively, and it wouldn’t show the potential capabilities of a camera like the Sony A1 which would be limited to a 4GB buffer. However, cameras with a smaller buffer like a Nikon Z9, could show better performance with some of those slower cards because they would not be used as often under the throttled conditions. While these slower cards do show tested results significantly slower than their rated performance, their peak bursts were actually showing closer to those rated numbers.

In other words, if you have a Nikon Z6 or Z7 with only a 2GB buffer, you may not notice the difference between a super-fast card or a slower card, especially since those early CFexpress cameras were still only using one PCIe 3.0 lane anyway. The new cameras like the Z9 are looking like they are taking advantage of the dual lanes of the CFExpress Type B cards.

Best CFexpress Type-B Memory Card Reader

Although I can’t see the full speeds of USB 3.2 gen 2 2×2 with a 2018 Macbook Pro, the Lexar CFexpress Type-B reader is clearly performing better than the other brands. I have two other Prograde readers a Pergear reader, a Sandisk reader, and an Angelbird reader. If you’re on a USB 3.1 or M1 Mac, it won’t matter which reader you use since the speeds will be throttled by the bus throughput.

I recommend these two readers unless you use Angelbird cards, then go with the Angelbird reader so you can update the firmware. 

See the Best CFexpress Type B Memory Card Readers for more information.

Lexar CFexpress Type B USB 3.2 – Amazon / B&H

If you can’t take full advantage of USB 3.2 setup or need UHS-II, the Prograde UHS-II + Cfexpress reader is only slightly slower, most would never notice the difference.

Prograde UHS-II + CFexpress – Amazon / B&H

The Prograde readers all now support the faster Sandisk interface so a lot of those UHS-I cards now run properly at the 170MB/s read speeds.