Best Memory Card Sony A6400 | In-Camera Benchmarks

A UHS-I and UHS-II SD memory card speed test comparing the performances between all the most popular memory cards in the Sony A6400. Use this guide to find the best and fastest memory cards for your Sony A6400.

Sony A6400 – Amazon / Adorama / BHphoto

Best Memory Cards Sony A6400

Like with Sony A6300 and A6500, we’re seeing a slight memory card buffer bottleneck of around 38-39MB/s on the Sony A6400. This is either happening with the processor or with some other hardware interface. 

Because of this, you will not need to buy the fastest memory cards available, but any decent memory card will due, but there are some brands I recommend more than others.

The Sony A6400 does not use UHS-II technology so it’s better to spend your money on UHS-I cards but to take advantage of 4k video, you will need U3 memory cards.

Top 5 Recommended Memory Cards For The Sony A6400

Here are the top-performing UHS-I memory cards for the Sony A6400. You only need UHS-I cards for this camera since it does not support UHS-II and it only has a single memory card slot. Sony does not specify the maximum capacity of memory cards that the camera can use.

Sony A6400 In-Camera Memory Card Speed Test

This memory card list includes the in-camera speeds, which are calculated by how much time it takes to clear the buffer against how much data was written. You can sort by category, however, since most of the cards have similar performance in the Sony A6400, it won’t make a huge difference which card you choose, just get any trusted brand and as long as it is a U3 card, it will work reliably with Sony cameras. See the recommended memory card list below.

As you can see from the chart, all the cards are getting a similar performance. We’ve mostly stopped testing U1 memory cards as they do not meet the requirements for 4k in most cameras and the U1 technology at this point is pretty much obsolete for anyone looking to take full advantage of all the features a Sony camera.

Sony A6400 Best Memory Cards For 4k Video

The Sony A6400 has a light 4k video codec of 100mbps which translates to about 12.5MB/s. Any of the U3 cards will work for video in the Sony A6400 (except Samsung SD cards which have compatibility issues).

You must use a U3 memory card!

When deciding which size memory card is best for video, you should be sure to get an SDXC card which is any card 64GB or larger because these cards use a 64-bit file system that allows you to record clips longer than 4GB. If you go with a 32-bit card, known as SDHC, you will see what’s called chaptering. This is where long clips are broken into 4GB chunks. Sometimes this is good, sometimes this is bad. I actually prefer this on my GoPro Hero 7 where I often have very long clips because it allows me to delete huge chunks of what I don’t need.

Memory Card Codes – What They All Mean

When you’re buying memory cards there are a few important numbers you need to pay attention to.

U1, U3 – U1 Minimum Write Speed 10MB/s – U3 Minimum Write Speed 30MB/s

V30, v60, v90 – V30 Minimum Write Speed 30MB/s, V60 60MB/s, V90 90MB/s

SDHC, SDXC – SDHC is a 32-bit file system 4GB file size limit. SDXC 64-bit file system

UHS-I, UHS-II – UHS-I – Single row of contacts, UHS-II – Two contract row for more than double the performance.

A1 or A2 – Now some memory cards are using a type of cache that improves the random read and write access. These cards are designed for running apps and will offer no benefit to photography or video.

Where To Buy Memory Cards – Avoid Counterfeit

There are still a lot of counterfeit memory cards out there so you need to be careful where you buy cards. It looks like this last year there has been a lot of shifting around of Sandisk stock at Amazon, so they could be cleaning up their inventory and I personally have never seen a counterfeit card from Amazon. Ebay is still a horrible place to buy memory cards. 

The best place to buy memory cards is at certified stores that deal directly with each brand. I always try to buy my cards from BHphoto, Adorama, Best Buy, Walmart, Target, etc. While I’ve never had any issues with Amazon, they allow a lot of retailers on their site and the rumor is they use to mix inventory so you never knew what you were getting for sure.

Test Your Cards First!

One of the best things you can do to test if you have a counterfeit card or not is to test it.

How do you test for Counterfeit cards?

Easy, fill the card up to its max capacity.

Usually, counterfeit cards have a hacked memory controller, so that 32GB or 16GB cards will actually tell the camera or your computer that it’s a 64GB or 128GB card. You won’t notice this at first, you might even go weeks before you reach the real capacity of the card then suddenly the card fails.

To check for counterfeit memory cards, the simplest thing you can is to completely fill it, either by dragging files onto it from your computer, or recording video until the card is full.

Best Memory Cards Sony A6400 Conclusions

Since the Sony A6400 is not very demanding of memory cards with a 38-39MB/s speed limit and a nice 1GB buffer, it makings buying memory cards a lot easier since most modern cards can keep up with this rate. I wouldn’t buy UHS-II cards unless you have another camera that can take advantage of that tech, otherwise, I would only buy UHS-I cards since they are much less expensive.

Buy from a trusted dealer and you won’t have any issues with counterfeit cards. All of the brands listed (except the two U1 cards I still test) now work great with no problems and Sony firmware continues to improve the stability and reliability of memory card performance.