The Canon M6 II shoots 4K video at 300Mbps, meaning you’ll need a memory card to maintain a data stream of 37.5MB/s.
While it seems UHS-I memory cards can handle this task, no UHS-I memory card guarantees a minimum write speed greater than 30MB/s, and you will need V60 UHS-II cards as a minimum to guarantee performance.
Recommended Memory Cards For The Canon M6 Mark II
The Canon M6 II supports UHS-II memory cards in two basic speed classes, v60 and v90.
V60 SD cards are great because they are fast enough for 4k video but still offer great value with their price and size.
V90 SD cards are the fastest available and are very useful for clearing that buffer quickly when shooting a 14fps continuous burst.
Here are the top 5 recommended cards with their in-camera speeds.
| Recommended Memory Cards | Canon M6 Mark II Speed | USB Write | USB Read | Price |
| UHS-II V90 | ||||
| Sony G Tough | 108.37 MB/s | 201.0 | 256.8 | Amazon |
| ProGrade V90 | 107.09 MB/s | 164.9 | 258.2 | Amazon |
| Sandisk Extreme Pro 300MB/s | 106.80 MB/s | 190.5 | 258.5 | Amazon |
| UHS-II V60 | ||||
| Delkin Prime v60 | 76.09 MB/s | 89.1 | 252.8 | Amazon |
| Sony M Tough | 74.72 MB/s | 91.6 | 253.6 | Amazon |
In-Camera Buffer Tests
We test every card available at the time to gather in-camera benchmarks. This is done by shooting a few continuous burst sequences until the buffer is full, and then I measure the time it takes the buffer to clear against the amount of data written.
Canon M6 Mark II Camera Specs
| Sensor: 32.5MP APS-C CMOS Sensor Processor: DIGIC 8 Image Processor SD Cards Slot: Single Slot UHS-II Continuous Burst: 14 fps Video: 4K at 25p/29.97p 300Mbps Maximum Memory Card Size: No Limit How Big Is The Buffer? 850MB est. How Many Shots To Fill Buffer? 26 What Size Are The Raw Files: 35MB How Long To Clear Buffer? 6sec |
Also, check out the guide for the accessories for the Canon M6 Mark II.
Best Cards for 4k Video
If you’re buying the Canon M6 Mark II for 4k video, there are a few things you need to know when shopping for memory cards.
Unlike the Canon M50, the M6 II has 100% sensor coverage when hooting 4k and 1080p.
4k Video will record at a bitrate of 300Mbps, while 1080p will record at a bitrate of 90Mbps.
300Mbps equals 37.5MB/s
90Mbps equals 11.25MB/s.
This means that for shooting 4 K video, you’ll need a card that runs at a minimum speed of 37.5MB/s. But you’ll want a card with a rating faster than that, such as v60 cards, so you can maintain a minimum data rate of 60MB/s.
In other words, if you’re shooting 4K video on the Canon M6 II, you’ll need a v60 UHS-II memory card to comply with the specs fully.
SD Memory Cards Canon M6 Mark II | Bottom Line
The Canon M6 II is a powerful little beast of a camera, and I’m very excited to see Canon supporting its APS-C line with such amazing specs and solid build quality.
Because the camera takes UHS-II memory cards, you can turn it into a high-performance continuous shooting machine or save money using slower v60 UHS-II cards or even UHS-I cards. The choice is yours.
Regarding size, you’ll probably want a card no smaller than 64GB, but many people are now going with 128GB cards.
What the Buffer Clear Time Means in Practice
The M6 II has an 850MB buffer and fills it in roughly 26 RAW shots at 14fps — about 1.9 seconds of continuous shooting. With a fast V90 card, the buffer clears in around 6 seconds. That is a genuinely quick clear time for an APS-C mirrorless. With V60 cards the clear time extends slightly, but still fast enough that a brief pause between bursts is barely noticeable in most shooting situations.
For sports and wildlife, this means a couple seconds of full-speed shooting, a short pause, and you’re back up. The tested V90 cards — Sony G Tough at 108.37MB/s, ProGrade V90 at 107.09MB/s, and Sandisk Extreme Pro at 106.80MB/s — all delivered very similar real-world performance in-camera, so the differences between them are negligible for most shooting.
Can I Use a microSD Card in the Canon M6 Mark II?
The Canon M6 Mark II uses a full-size SD card slot. MicroSD cards work with an adapter, but from experience they can lose connection inside the adapter — I wouldn’t use one for anything critical. See the microSD memory card guide if you need to use one.
Canon M6 Mark II Memory Card FAQ
Can I use a UHS-I card for 4K video on the M6 II?
It’s risky. The M6 II records 4K at 300Mbps, which requires a sustained 37.5MB/s write speed. UHS-I cards are guaranteed to only 30MB/s minimum — and real-world sustained write speeds often fall below rated figures. A V60 UHS-II card is the safe minimum for 4K. For 1080p at 90Mbps (11.25MB/s), a good UHS-I U3 card handles the load without issue.
Is V90 worth it over V60 for the M6 II?
For 4K video, no — both V60 and V90 handle the 300Mbps bitrate comfortably. The difference shows in burst recovery: V90 cards clear the 850MB buffer faster after a continuous burst sequence. If you’re shooting fast action at 14fps and need quick turnaround between bursts, V90 is the better choice. For general photography and video work, V60 offers better value without a practical performance penalty.
What card size should I buy for the Canon M6 II?
RAW files from the 32.5MP sensor run around 35MB each. At 14fps, a single two-second burst generates over 350MB. For a mix of RAW stills and 4K video, 128GB is a practical minimum. If you’re shooting events or longer sessions without an opportunity to offload, 256GB keeps you from card-swapping at a critical moment.
Does the M6 II have two card slots?
No — the M6 II has a single UHS-II SD card slot. There is no backup slot, so card reliability matters more than it would in a dual-slot body. Stick with established brands: Sony Tough G, Delkin Power, Sandisk Extreme Pro, or ProGrade Cobalt. If you’re shooting events or anything irreplaceable, carry a spare card and swap between sessions rather than risking a single card for an entire day.
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