Best Memory Cards for the Sony A6400 – 38 Cards Tested In-Camera

The Sony A6400 has a single SD card slot that runs at UHS-I speeds, and the camera, not the card, sets the speed limit. It writes to the card at about 40 MB/s at best, so Sony gave it a large buffer, about 1GB by my testing, to keep bursts going. In my in-camera tests of 38 cards, 16 of the 17 U3 and V30 UHS-I cards wrote 36.0–39.4 MB/s, and every UHS-II card, including V90 cards, wrote 38.5–40.4 MB/s, because UHS-II cards run in UHS-I mode in this slot. Buy a good U3 or V30 UHS-I card; the A6400’s highest video bitrate is 100 Mbps (12.5 MB/s), so any U3 card covers every mode. Full camera impressions are in my Sony A6400 review.

How I tested: I shot compressed RAW, the only RAW format the A6400 records, at Hi+ (11 fps), held the shutter until the buffer filled, then measured how long the camera took to write the burst to the card. In-camera speed is the data written divided by the time it took to clear the buffer. Each burst wrote about 1.23–1.43 GB. My test scene is fairly simple, so files from more detailed scenes can be larger. I don’t test with RAW+JPEG, because processing the JPEGs puts more load on the camera’s processor than on the card, which muddies the card speed results.

Best Memory Cards for the Sony A6400

All but one of the U3 and V30 cards I tested landed within a few MB/s of the camera’s limit, so pick a reliable UHS-I card in the size you need. Only the two slowest cards in my test, the SanDisk Ultra (U1) and the Toshiba Exceria, fell well behind, taking 41–46 seconds to clear a burst instead of about 32–34.

	Best value: SanDisk Extreme UHS-I (V30). The 128GB card writes 99 MB/s in my reader tests, more than double what the A6400 can write, so a faster card won’t make this camera any quicker. V30 covers every A6400 video mode.
	If you shoot other cameras too: SanDisk Extreme PRO UHS-I (V30). The 128GB card writes 125 MB/s in my reader tests, versus 99 MB/s for the Extreme. The A6400 can’t use that extra speed, but a faster UHS-I camera can.
	Also good: Delkin Advantage UHS-I (V30) 64GB. Writes 78 MB/s in my reader tests, still about double the A6400’s limit. Reads are slower, about 96 MB/s, so copying files to your computer takes longer than with the SanDisk cards.
	If you plan to upgrade: Lexar ARMOR Gold V60. UHS-II cards run at UHS-I speeds in the A6400, so it won’t shoot any faster here. But it wrote 194 MB/s in the Sony A7V, the fastest V60 card I’ve tested in-camera, and reads 253 MB/s in a UHS-II reader.

Why Card Speed Barely Matters on the A6400

On the Sony A6400, the fastest card I tested cleared a full RAW burst at most about three seconds sooner than the other good U3 cards. Each burst wrote about 1.3 GB, and at the camera’s limit that took 32–34 seconds on any good U3 card, so you only notice card speed if you shoot long bursts back to back.

Like the A6300 and A6500, the A6400 tops out around 40 MB/s regardless of the card, so the A6400 relies on its big buffer, not card speed, to keep up with bursts. It was probably cheaper for Sony to pair a slow memory controller with a big buffer than to build a faster one.

UHS-I or UHS-II Cards for the Sony A6400?

UHS-I. UHS-II cards fit the A6400’s slot but run at UHS-I speeds: the 20 UHS-II cards I tested wrote 38.5–40.4 MB/s, the same range as the best UHS-I cards. I wouldn’t get UHS-II cards unless you have another camera that can use them; otherwise, I’d only get UHS-I cards, since they’re much cheaper. If you’re moving to the Sony A6700, it has a UHS-II slot, and the fastest V90 cards wrote 213–223 MB/s in it.

Current SD Cards I Recommend

I update this list as new cards come out. The speeds are from my card reader tests. Every U3 or V30 card here writes faster than the A6400 can, so any of them will max out the camera; the in-camera results below show where that limit is.

Which Cards You Need for Video

On the Sony A6400, the highest bitrate is 100 Mbps, in 4K and in 120p HD, which works out to 12.5 MB/s, and Sony lists U3 cards for it. Lower bitrates work on U1 or Class 10 cards. Sony’s requirements include proxy recording at the same time.

Format	Bit rate	Card Sony lists
XAVC S 4K (30p/25p/24p)	100 Mbps	SDHC/SDXC, U3
XAVC S 4K (30p/25p/24p)	60 Mbps	SDHC/SDXC, U1 or Class 10
XAVC S HD 120p/100p	100 Mbps	SDHC/SDXC, U3
XAVC S HD 120p/100p	60 Mbps	SDHC/SDXC, U1 or Class 10
XAVC S HD (60p and lower)	50 Mbps or lower	SDHC/SDXC, U1 or Class 10
AVCHD	24 Mbps or lower	SD/SDHC/SDXC, U1 or Class 4

The table is from the Sony A6400 help guide.

SDHC vs SDXC: Do You Need a 64GB Card?

No. Sony lists SDHC cards (32GB and smaller) for every A6400 video mode, including 4K at 100 Mbps. The catch is that SDHC cards split long XAVC S clips into 4 GB files, which Sony’s PlayMemories Home software can join back into one file. SDXC cards (64GB and larger) record each clip as one file. Split files aren’t always bad; I actually prefer them on my GoPro for long clips, because I can delete big chunks I don’t need.

What Size Memory Card Do You Need for the Sony A6400?

For most people, 64GB or 128GB. Sony estimates a 64GB card holds about 1 hour 15 minutes of 4K at 100 Mbps, or about 2,400 RAW files. If you shoot a lot of 4K, a 256GB card holds about 5 hours 15 minutes.

Sony A6400 Record Times

These are Sony’s estimated recording times.

Format	32GB	64GB	256GB
XAVC S 4K 100 Mbps	35 min	1 hr 15 min	5 hr 15 min
XAVC S 4K 60 Mbps	1 hr	2 hr 5 min	8 hr 35 min
XAVC S HD 120p 100 Mbps	35 min	1 hr 15 min	5 hr 15 min
XAVC S HD 60p 50 Mbps	1 hr 15 min	2 hr 35 min	10 hr 25 min
XAVC S HD 60p 25 Mbps	2 hr 25 min	5 hr	20 hr 10 min
RAW stills	1,200	2,400	9,600

Sony A6400 Memory Card Benchmarks

I tested every card in-camera: I fill the buffer with a burst, then measure how fast the camera writes it to the card. Time to clear is how long the camera took to write the burst. For reader benchmarks, see my SD card guide.

I tested these cards in 2019, and most of them have since been discontinued or replaced. Newer cards won’t change the results, because the A6400 is the bottleneck: every good U3 card and every UHS-II card I tested, up to 300 MB/s V90 cards, wrote at 36–40 MB/s. Use the results to see how the camera handles fast and slow cards; my current picks are at the top of the page.

Sony A6400 In-Camera Test Results: UHS-I SD Cards (Tested 2019)

Card	Class	In-camera write (MB/s)	Time to clear (s)
Sony Professional	U3	39.4	32
Verbatim Pro+	U3	39.4	32
Toshiba Exceria Pro	U3	39.1	34
SanDisk Extreme PRO (170 MB/s)	U3	38.7	32
SanDisk Extreme	U3	38.7	32
PNY Elite Performance	U3	38.7	32
SanDisk Extreme PLUS	U3	38.5	32
Transcend	U3	38.4	32
Sony (95 MB/s)	U3	38.0	32
Sony (94 MB/s)	U3	37.8	32
Delkin Advantage	V30	37.3	34
Kingston Canvas Go!	U3	36.9	33
Kingston Canvas React	U3	36.8	33
Verbatim Pro	U3	36.6	33
Lexar 633x	U3	36.5	34
Amplim 667x	V30	36.0	34
Toshiba Exceria	U3	28.5	41
SanDisk Ultra	U1	26.0	46

Sony A6400 In-Camera Test Results: UHS-II SD Cards (Tested 2019)

These cards ran in UHS-I mode, so they show what the A6400 can write, not what the cards can do in a UHS-II camera.

Card	In-camera write (MB/s)	Time to clear (s)
Angelbird AV PRO V90	40.4	34
Sony TOUGH G V90	39.6	31
Sony G	39.6	32
SanDisk Extreme PRO (300 MB/s)	39.3	32
Toshiba Exceria Pro	39.3	32
Delkin POWER V90	39.3	31
FreeTail Evoke Pro V60	39.3	32
Sony M	39.2	32
Delkin PRIME V60	39.1	32
ProGrade Digital V90	39.0	31
Amplim 1900x V60	39.0	32
Transcend V90	38.9	32
Hoodman Steel 2000x	38.9	32
Lexar 1000x	38.8	32
ADATA Premier ONE V90	38.8	32
Hoodman Steel 1500x	38.8	32
ProGrade Digital V60	38.8	32
Fujifilm Elite II	38.7	32
Lexar 2000x	38.6	32
Angelbird AV PRO V60	38.5	32

Each burst wrote 1.23–1.43 GB, which includes the 2–4 shots I usually take after the buffer fills, so use the time to clear to compare cards, not as an exact buffer size. The ProGrade Digital cards here are the older ProGrade V90 and V60, not the newer Iridium line.

Sony A6400 Specs That Affect Card Choice

Sensor: 24.2MP APS-C Exmor CMOS Processor: BIONZ X Memory Card Slot: 1 SD (UHS-I) / Memory Stick Duo Continuous Shooting: up to 11 fps (Hi+) Buffer: about 1GB (my estimate from testing) RAW Format: Compressed RAW only (12-bit during continuous shooting) 4K Datarate: up to 100 Mbps XAVC S (12.5 MB/s) HD Datarate: up to 100 Mbps at 120p (12.5 MB/s)

Sony A6400 Memory Card Quick Answers

What’s the fastest SD card for the Sony A6400?

The camera itself sets the speed limit here at about 40 MB/s, so any good U3 or V30 card is as fast as it gets. When I tested 38 cards in-camera, the fastest one hit 40.4 MB/s, and 28 of them landed within 2 MB/s of that mark. Every card in my current picks writes at least 78 MB/s in my reader tests, which is roughly double what the A6400 can use.

How big is the Sony A6400’s buffer?

It’s about 1GB, based on my tests with a slow SanDisk Ultra card. Because the camera caps out writing at roughly 40 MB/s, clearing that full buffer takes about 32–34 seconds on a good U3 card, stretching out to 41–46 seconds on the slowest cards I tested.

Can I use a microSD card in the A6400?

You can use one with an adapter, but I wouldn’t recommend it for anything critical. In my experience, microSD cards can lose connection inside those adapters, so you’re better off sticking to a full-size SD card in the A6400’s standard slot. If you really need to run one, check out my microSD memory card guide.

Buy from a reliable seller and you won’t have any trouble with fake cards. For more Sony cards, see my Sony A6700 and ZV-E10 II memory card tests, my guide to memory cards for Sony cameras, and my SD card guide for reader speed tests.