Best CFexpress Type-A Memory Cards – 18 Tested

CFexpress Type A (CFxA or CFeA) is the compact CFexpress format Sony uses in its newer cameras. It’s smaller (but thicker) and much faster than UHS-II V90 SD memory cards, and with prices down, some CFxA cards are now better value than V90 SD. I’ve tested 18 cards for burst and sustained write speed, so you can see which ones hold their speed once the SLC cache fills.

Quick Picks

• Fastest: Sony TOUGH G CF4.0. 1,552 MB/s burst write in my reader tests, with the Nextorage A2 AE (1,534 MB/s) and Nextorage A2 Pro (1,521 MB/s) right behind it.
• Best value: Lexar Professional SILVER. Its 640 MB/s reader write is well below the top cards, but in the Sony A7V, which caps CFxA cards around 310 MB/s, it performs the same as the fastest ones.
• Best warranty: Delkin BLACK CF4.0. Lifetime warranty with a 48-hour replacement guarantee, and 1,120 MB/s in my reader tests.

Table of Contents

• Quick Picks
• New CF4.0 CFexpress Type-A Memory Cards
• CFexpress Type-A Memory Card Benchmarks
• Reader Speed vs. In-Camera Speed (Sony A7V)
• What To Look For With CFexpress Type-A Cards
• How Are CFexpress Type A Cards Different Than CFexpress Type B?

New CF4.0 CFexpress Type-A Memory Cards

The CF4.0 interface is the latest technology in CFexpress Type-A memory cards. It doubles the bandwidth per PCIe lane, which is why CF4.0 Type A cards can burst past 1,500 MB/s in my reader tests. It doesn’t make the flash itself any faster, though, so once the SLC cache fills, sustained speeds still come down to the flash on the card. Right now, the biggest real-world benefit is faster offloads to your computer.

No camera has yet taken advantage of this new standard. So, you don’t need to worry about buying CF4.0 cards if they are the most expensive. However, this is where everything is going, so if you find a great deal, you’ll have at least a card ready or a future camera.

CFexpress Type-A Memory Card Benchmarks

To find the best CFexpress Type-A memory cards, I benchmarked each with the AJA system test on an M4 Mac mini using the Prograde CFx CF4.0 Type-A reader.

AJA System Test settings: Resolution: 5120×2700 5k Red / Test File Size: 4GB For Burst, 128 or 64GB for Sustain / Codec Type 16bit RGBA. Speeds are shown in Megabytes per second.

AJA produces an average based on transfer request size for the codec type I’ve selected, so it is more relevant to camera usage, which is almost always sequential and often with larger write blocks. I run typically 3 tests and take the best results for the burst speeds. For the sustain speeds test I run 2 tests and take the worst results which usually happens at the second run after the card is hot.

Want the full write-up on a single card? See my Sony TOUGH CFexpress Type A review and my Lexar CFexpress Type A review.

Reader Speed vs. In-Camera Speed (Sony A7V)

The AJA numbers above show what each card can do in a fast reader. In the camera, it’s a different story. I tested 17 of these cards in the Sony A7V, and every one landed between 307 and 312 MB/s, whether it writes at 527 MB/s or 1,552 MB/s in the reader:

Card	Reader Write (MB/s)	A7V In-Camera (MB/s)	Buffer Clear (sec)
Sony TOUGH G CF4.0 240GB	1,552	310	3.1
Nextorage A2 AE 500GB	1,534	310	3.1
ProGrade Iridium CF4.0 480GB	1,502	311	3.1
Delkin BLACK CF4.0 480GB	1,120	311	3.0
Lexar Professional SILVER 256GB	640	310	3.0
Exascend Essential 120GB	527	312	3.1

The A7V tops out around 310 MB/s, so a card with three times the reader speed doesn’t buy you anything in this camera. Buy on price, capacity, and warranty, and think of the fastest cards as a way to get faster offloads to your computer. Full results for all 17 cards are on my Sony A7V memory cards page.

You can see these cards benchmarked in various Sony cameras:

• Memory Cards For Sony A7V
• Memory Cards For Sony A1 II
• Memory Cards For Sony A9 III
• Memory Cards For Sony A1
• Memory Cards For Sony A7S III
• Memory Cards For Sony A7R V
• Memory Cards For Sony A7 IV

You can check out this Sony Guide To Memory Cards to see which Sony cards support CFxA cards.

What To Look For With CFexpress Type-A Cards

These CFxA cards work similarly to the SSDs in our computers. They often use a fast SLC (Single-level cell) flash as an initial, quick cache that might be a few gigabytes. Once that cache fills up, the card starts writing to much slower memory, like MLC. This affects their sustain speeds.

You can see that working with the Sony Tough cards with the I/O transaction data below.

The faster SLC flash memory is initiated quickly, and write speeds are very quick, but once the SLC flash is filled, files and the fast cache write to slower memory until the SLC flash is cleared for another write cycle.

In addition, thermal throttling can occur when the cards get very hot. Although cards sometimes run better once they are a little warmed up. Flash memory likes being hot, but the controller inside it doesn’t.

To avoid negative reviews, memory card companies are now listing the guaranteed write speeds of these cards. For example, most CFxA cards list the 400 or 200-speed class. Similar to how we had V60 or V90 with our UHS-II SD cards.

If the card has a 400 rating (the little 400 inside the film clapboard), it is guaranteed to sustain an average of 400 MB/s.

How Are CFexpress Type A Cards Different Than CFexpress Type B?

The main difference between CFexpress Type A and CFExpress Type B cards, aside from their size, is that Type B cards use two PCIe lanes while Type A cards use one. With CFexpress 2.0, that meant Type A cards topped out around 800 MB/s and Type B cards around 1,700 MB/s. CFexpress 4.0 roughly doubles both, which is why the CF4.0 Type A cards in my tests burst past 1,500 MB/s.

That puts today’s CF4.0 Type A cards on par with CF2.0 Type B cards, which makes Sony’s choice of the smaller format look pretty practical. The tradeoff is heat: pushing PCIe 4.0 speeds through a single lane can make these cards run hot.