CFexpress Type-A memory cards, also called CFxA memory cards, are a type of card that Sony has been using for many of their new full-frame mirrorless cameras.
CFexpress Type-A cards are a bit smaller, but thicker, and quicker than UHS-II memory.
Many of the new Sony cameras accept both CFexpress Type-A and UHS-II memory cards but need the quicker CFx Type-A cards for some slow-motion video functions like 4k120 to record in the S & Q mode. They are also helpful in clearing the buffer quicker in many of the faster sports and action-focused cameras like the Sony A9 II.
Fastest CFx Type-A Memory Cards
There are a few CFexpress Type-A cards on the market now, and they’ve become larger and cheaper. Some are now affordable enough to be a reasonable option for photographers who are unsure about what kind of card to choose.
These benchmarks are done with an AJA system test with a Macbook Pro, using the Prograde CFx Type-A reader.
The software used was AJA System Test. Resolution: 5120×2700 5k Red / Test File Size: 4GB / Codec Type 16bit RGBA. Speeds are shown in Megabytes per second.
CFxA Memory Cards | Rated Write | Rated Read | Rated Sustained | USB Write | USB Read | Sustain Tested | Links | ||
---|---|---|---|---|---|---|---|---|---|
CFExpress Type-A | |||||||||
Sony Tough 960/1920GB | 700 | 800 | 200 | Check Price | |||||
Sony Tough 80/160/320/640GB | 700 | 800 | 400 | 641 | 852 | Check Price | |||
Lexar Gold Series 80/160GB/320GB | 800 | 900 | 400 | 825 | 886 | Check Price | |||
Lexar Silver Series 160/320GB | 700 | 800 | 200 | 776 | 861 | 687 | Check Price | ||
Delkin Black 160GB | 790 | 880 | 400 | Check Price | |||||
Delkin Black 80GB | 730 | 880 | 400 | 639 | 852 | Check Price | |||
Delkin Power 160GB | 790 | 880 | 400 | Check Price | |||||
Delkin Power 80GB | 730 | 880 | 400 | 641 | 847 | Check Price | |||
ProGrade 160GB | 700 | 800 | 400 | 691 | 845 | Check Price | |||
AngelBird 1TB disc. | 730 | 820 | 650 | Check Price |
You can see these benchmarked in various Sony Cameras.
Or you can check out this Sony Guide To Memory Cards to see which Sony cards are supporting CFxA cards.
What To Look For With CFxA Cards
The read and write speeds used by the manufacturer are not always accurate to what you get in the real world. They don’t necessarily lie, because of the way the cards work, but it’s not always honest. Fortunately, sites have this one have been around for the last decade posting real numbers, and these memory card companies now try to be a little more transparent with what their cards can do by listing the proper sustained speeds.
These CFxA cars work similarly to how the SSDs in our computers work. They often have a fast SLC (Single-level cell) flash used as an initial quick cache, that might be a few GB big, then once that cache gets filled, the card starts writing to much slower memory, like MLC.
You can see that working here with the Sony Tough cards with the I/O transaction data below.
The faster SLC flash memory gets initiated and the write speeds are very quick, but then once the SLC fast type of flash is filled up, the files as well as the fast cache write to the slower memory until the fast flash is cleared for another write cycle.
On top of this, thermal throttling can occur when the cards get very hot. But also, cards run better sometimes once they are a little warmed up. Flash memory likes being hot, but the controller in the flash doesn’t.
To avoid negative reviews, memory card companies are now listing the guaranteed write speeds of these cards. For example, most of these CFxA cards list the 400-speed class. Similar to how we had V60 or V90 with our UHS-II SD cards.
If the card has the 400 rating, (the little 400 inside the film clapboard) the card is guaranteed to sustain an average of 400MB/s.
Although, we don’t exactly see that here, if we average these I/O transactions we get something similar to 400MB/s. If the little 400 film clapboard is not present on the card, look for the manufacturer’s sustained write speeds.
How Are CFexpress Type A Cards Different Than CFexpress Type B?
The main difference between type A and type B cards besides their size is that Type B cards have a two-lane system for speeds up to 1700MB/s while Type A cards only have a one-lane throughput for a top speed of 800MB/s.
With PCIe 4.0 now on the market, we can expect CFxA cards to get significantly faster. What’s cool is we should eventually see PCIe 4.0 CFxA cards that are as fast as our current PCIe 3.0 cards CFxB cards, making this CFxA choice a pretty practical play by Sony as the cards are much smaller and lighter. However, they could potentially have more issues with heat when running these blazing-fast PCIe 4.0 speeds on a single lane. We’re currently seeing these issues with the M.2 Gen 5 drives on our computer.
We’ll have to see where advancements with this technology take us, but this CFxA tech is looking very exciting.
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