Best Memory Cards Sony A7sIII – Real Benchmarks

The Sony A7sIII has a very unique setup with dual UHS-II SD card slots that can also take the CFexpress Type A cards. But you might not need CFexpress cards. This guide will help you find the best memory cards for the Sony A7sIII and hopefully save you some money.

Sony A7sIII Memory Card Recommendations

You only need CFexpress type A cards if you record S&Q at fast frame rates with XAVC S-I.

UHS-II cards usually have two-speed classes associated with them, V90 and V60. 

V90 UHS-II cards offer a minimum bitrate of 90MB/s. The minimum requirement for 600Mbps ( 75MB/s ) H.264.

V60 UHS-II cards offer a minimum bitrate of 60MB/s. Minimum requirement 280Mbps ( 35MB/s ) H.265.

You can shoot with high frame rates with S&Q with XAVC HS (H.265) and XAVC S (H.264) with V60 or V90 UHS-II cards, but for All-I with XAVC S-I (H.264), you will be required to use a CFexpress Type A card – this applies to both 4k and HD modes.

Note*: CFexpres Type A card cap out at around 240 MB/s. The reason for this is because the Sony A7sIII pretty much gets a bottomless buffer with these cards and I can’t produce data faster than 250MB/s when doing a continuous burst. These cards will still record at more than twice the speed of UHS-II cards and will be required for S&Q 4k recording with intra-frame compressions.

Also, see my Sony A7sIII List of Accessories.

Memory Card In-Camera Benchmarks

These benchmarks are measured by shooting a series of bursts in Uncompressed RAW until the buffer fills, how much data is written between the time it took to clear the buffer is then calculated.

Speeds are in MB/s.

Notes: For some reason, I couldn’t get my Sandisk card to perform correctly in the Sony A7sIII. It’s usually a great card and works in most Sony cameras including the Sony A1. It’s likely there was a connection issue with the pins on the card to the camera. I have since replaced the card since there was a new model.

Also, my Sony M was of the serial that had a recall issued and the camera rejected it. For this test, I used an older Sony M card that is slower. New Sony M cards should perform better. You can check the Sony A1 Memory Card Test to see how they perform.

Sony A7sIII Memory Cards | What You Need To Know

The Sony A7sIII has a very interesting setup, it allows for two different types of memory cards in the same slot (not at the same time).

And since both memory card slots are UHS-II and CFe compatible, you can mix and match your setup.

What’s the difference between CFexpress Type A and SD Cards?

Quite a bit, but it mainly comes down to size and speed. CFexpress Type A cards are much faster and slightly smaller.

For more information on the difference between CFexpress Type A cards and UHS-II SD and to see which cards are currently the best, check out this guide on the fastest CFexpress Type A cards.

Do you need CFexpress Type A cards for the Sony A7sIII?

Only if you shoot S&Q at high frame rates with XAVC S-I.

XAVC HS and XAVC S will work with V60 or V90 UHS-II memory cards.

What is the S & Q setting and why do you need it? 

S & Q stand for slow and quick. It creates a file that will be played back in slow motion set to your base frame rate. Footage plays back in slow motion inside the camera or in your editing software without further conversion.

The advantage of S&Q mode is it records at a very high bitrate, in some settings up to 1200Mbps, then dumps that to the set playback frame rate resulting in a much higher quality image compared to the standard high frame rate recordings.

For example with XAVC S-I 4k, you can get a 60fps file at 600Mbps, or a 24fps file at 240Mbps.

When shooting S & Q you will need to use CFexpress Type A cards for XAVC S-I which is the All-I compression at H.264. For editing with slow-motion video, this will be the easiest file for your computer to handle.

Sound will not be recorded in the S & Q mode.

For now, the price of CFexpress Type-A cards is very high. You may want to forgo shooting S&Q All-I footage or use a smaller CFexpress Type A card just for when 120p S&Q recording is needed with the All-I compression.

Alternatively, if your computer can handle XAVC HS, then H.265 will not only produce smaller files, but the quality will also be very high even though it’s a Long GOP compression. But be aware that many graphics cards are not going to decode and encode 4k 4:2:2 as a standard and you may need to drop to 4:2:0 for a smooth experience editing with H.265. Otherwise, you might need to use a proxy workflow. Likely future GPUs and CPUs will make this bit-depth standard so you will just need to test what you have or see if there is an appropriate upgrade path. Almost no big tech review channels are aware of the difference between 4:2:2 or 4:2:0 so some of this information will be difficult to find.

S&Q Bitrates & Modes

Use the table below to see the various bitrates of the different recording modes.

The base bitrate will be the same regardless of Frame Rate the camera records at, but each column shows the bitrate for the Rec. Frame Rates. Meaning, what you should expect to see with the final file at the set frame rate.

Sony A7sIII Memory Card Capacity

The Sony A7sIII can take any size memory card. If you want to use a 1TB memory card, the camera will take it. Keep in mind, if you use 32GB cards, you’ll only be able to format the card in a 32-bit filesystem, and you won’t be able to record clips larger than 4GBs.

Sony A7sIII Specs

Best Memory Cards For 4k Video

Sony A7sIII Video Specs & Recording Modes

There are a lot of different record modes with different Sony codecs.

What’s new to the Sony A7sIII is the XAVC HS and the XAVC S-I.

What’s the difference between XAVC HS, XAVC H-I, and XAVC S?

All three containers are capable of recording 10-bit 4:2:2. The main difference is H.265 vs H.264.

XAVC HS allows for H.265 recording but is Long GOP.

XAVC S and S-I still only record to H.264. The S-I variant is an all intra recording – meaning there is a keyframe on every frame. XAVC S uses Long GOP.

H.265 offers better compression performance at a lower bandwidth which makes it a much more efficient file. H.265 can produce on average 50% better quality at a similar file size as H.264 depending on the scenes.

The disadvantage of H.265 is it is harder on the CPU to decode and it will often require you to work with proxies when editing, especially XAVC HS which is Long GOP.

H.264 is an older codec that was used by all the older Sony cameras. H.264 will support 10-bit at a 4:2:2 subsampling but it’s not as efficient as H.265. You can still get great quality out of H.264 since Sony increased the bitrate to 600Mbps with H.264.

This will give you similar quality to H.265. Most computers will be able to edit these files without any issues, so you’ll have to test for yourself the advantages and disadvantages of each system. I personally just edit with H.265, using the proxies in Premiere.

Record Limit: Unlimited
Audio FIle Format: AAC, Linear PCM

Should You Use XAVS HS or XAVS S-I?

You should use XAVC HS with the H.265 recording when you can. It is a better codec and then you should develop a proxy post-production workflow in Premiere to speed up the editing process. It’s incredibly simple to do once you’ve got it all set up. It’s worth the file size advantage and image quality advantage.

If you need to get to editing quickly without proxies, you’ll likely want to shoot with XAVC S-I which records H.264. Keep in mind the file sizes will be much larger if you’re using the max quality of 600Mbps and you should technically use more expensive V90 cards – although so far in my tests the v60 cards are working well for 600Mpbs recordings and the camera will not reject them.

What Size Memory Card Is Best?

The size of the memory cards you’ll need really depends on record settings and the type of video you’re shooting. You’ll probably want to start with a 128GB card which gives you 61 minutes when recording with the 280Mbps H.265 bitrates. This is going to be enough for short videos that take a few hours to shoot. 

If you shoot 600Mbps with H.264 because you don’t want to deal with the additional post-processing labor involved with H.265, then you may want to start with a 256GB card.

On long shoot days or big projects, you may either want to go with a bigger card or clear off the cards midday, which means you have to bring some sort of computer and backup drives. So this all depends on your budget and workflow.

Sony A7sIII Record Times – Memory Card Capacity

Here are the record times for 4k bitrates based on a few memory card sizes.

Use this table to see the memory card capacity with different record settings.

Transferring File With USB-C vs Memory Card Reader

The USB-C port on the Sony A7sIII can produce very fast read speeds if you use the correct USB 3.0 or 3.2 cables.

Using the Sony CFexpress Type-A card am able to write to the card at 100MBs and read from the card at 296MBs.

Using the Sony G UHS-II Tough memory card I am able to write at 37.9MBs and read at 201.8MBs.

You’ll get better performance with a USB-C 3.2 memory card reader (I use this Prograde Reader on Amazon since it has both UHS-II and CFexpress Type A slots), but the camera is producing acceptable speeds for transfer via USB-C if needed.

Avoiding Counterfeit Memory Cards

Counterfeit memory cards still plague many online retailers and you can end up with them if you’re not careful.

To avoid counterfeit cards there are a few precautions you can take.

First, buy from trusted stores only. BHphoto, Adorama, etc. If you buy from Ebay, or Amazon, make sure that you still select a trusted seller. Even then occasionally you can get mixed inventory. I haven’t had it happen when buying from Amazon personally, but I’ve heard about it happening in Europe. Most of the time these counterfeit cards look too good to be true, or they are extremely popular cards. 

How to test for counterfeit memory cards?

Counterfeit memory cards are often made by hacking the memory card controller to report a false capacity. For example, they’ll take a 32GB card, and hack it to read as though it’s a 128GB card.

Everything will work fine for days or weeks until you cross that 32GB threshold, then the card fails.

What you can do with the Sony A7sIII is set the camera to record video at 600Mbps, and let it run on each card you buy until it fills the card. If the card reaches rated capacity then it’s most likely authentic. 

Best Memory Cards Sony A7sIII Conclusions

Shopping for memory cards for the Sony A7sIII is a little tricky since it takes two different types of cards. When CFexpress Type A cards come down in price it would make sense to just buy two of those and you’ll have a system that can handle any record mode.

If you’re just shooting fairly casually and you don’t need that S&Q record mode and you’re fine with capturing 120p the normal way, then any UHS-II card will work fine.

The big takeaway would be to remember

UHD 4k H.265 XAVC HS, v60 UHS-II cards are fine.

UHD 4k H.264 XAVC S-I, you will need v90 UHS-II cards.