On this page · 11 sections
- What a V30 SD Card Guarantees
- UHS-I vs UHS-II: Why Insta360 Says UHS-I Only
- A1 vs A2 SD Card Ratings and Why Video Ignores Them
- Micro SD Card for Action Camera Requirements by Brand
- SD Card for 4K Video: Match the Card to the Bitrate
- How Much Video Can 128GB Hold?
- exFAT vs FAT32 on an Action Camera Card
- How to Format a Micro SD Card for an Action Camera
- What Manufacturers Don't Publish
- Frequently asked questions
- Buy the Class Your Manual Names, Then Format It in the Camera
◆ Key takeaways
- V30 means a minimum write speed of 30MB/s, as defined by the SD Association. Every manufacturer here names V30.
- Insta360 wants UHS-I cards formatted exFAT, up to 1TB. It advises against UHS-II and UHS-III cards.
- At 120Mbps, DJI's published maximum bitrate, a 128GB card holds roughly 2 hours 20 minutes.
- Format any micro SD card for action camera use in the camera itself before the first shoot.
What a V30 SD Card Guarantees
A V30 SD card guarantees a sustained sequential write speed of at least 30MB/s. The V stands for Video Speed Class, and the number is the floor in megabytes per second. On the packet, the big "up to" figure is usually a read speed, which tells you how fast footage comes off the card.
The SD Association's speed class definitions give each symbol its own minimum write speed, and none goes past V90's 90MB/s.
| Speed symbol | Minimum write speed | Highest bitrate it covers |
|---|---|---|
| Class 10 | 10MB/s | 80Mbps |
| U1 | 10MB/s | 80Mbps |
| U3 | 30MB/s | 240Mbps |
| V6 | 6MB/s | 48Mbps |
| V10 | 10MB/s | 80Mbps |
| V30 | 30MB/s | 240Mbps |
| V60 | 60MB/s | 480Mbps |
| V90 | 90MB/s | 720Mbps |
Source: SD Association (December 8, 2022). Bitrate column calculated as MB/s times 8.
The SD Association's speed class page adds that "V60 and V90 are used in UHS-II mode or faster." In a camera built around UHS-I cards, a V60 card sells you a guarantee the camera never calls on.
U3 SD Card and Class 10 Markings
A U3 SD card promises the same 30MB/s minimum write as V30, and U1 promises 10MB/s. U3 is a UHS Speed Class mark and V30 a Video Speed Class mark, so many cards print both. Every card DJI recommends for the Osmo Action 6 and Osmo Action 5 Pro carries U3 and V30.
UHS-I vs UHS-II: Why Insta360 Says UHS-I Only
UHS-I vs UHS-II describes the bus between card and camera. The SD Association rates UHS-I at 50MB/s or 104MB/s depending on mode. UHS-II adds a second row of pins and reaches 156MB/s full duplex or 312MB/s half duplex.
Insta360's manuals for the X3, X4, X5 and X6 say not to use UHS-II or UHS-III cards, and the GO Ultra manual warns they "may be incompatible."
Card makers still market UHS-II microSD cards to camera owners. Every recording rate published for these cameras sits far below UHS-I's 104MB/s, so the extra bus speed only helps when you offload through a UHS-II reader.
A1 vs A2 SD Card Ratings and Why Video Ignores Them
A1 vs A2 SD card ratings measure random access, the scattered small reads and writes a phone makes when it runs apps from a card. The SD Association sets A1 at 1,500 random-read and 500 random-write IOPS. A2 raises that to 4,000 and 2,000, and only works as A2 when both host and card support it.
An action camera writes one long sequential file, so the V rating decides whether recording keeps up. A2 on the label does no harm and adds nothing to recording. Insta360's X5 card list mixes A1 and A2 SanDisk Extreme cards.
Micro SD Card for Action Camera Requirements by Brand
The table lists what each manufacturer publishes for a micro SD card for action camera use, taken from its own manual or spec page.
| Camera | Card type and speed | File system | Max capacity |
|---|---|---|---|
| Insta360 X6, X5, X4, X3, Ace Pro 2 | UHS-I, V30 or higher | exFAT | 1TB |
| Insta360 GO Ultra | UHS-I, V30 or higher | exFAT | 2TB (1TB on one page) |
| Insta360 GO 3S | No card slot | n/a | n/a |
| GoPro HERO13 Black, MISSION 1 | v30 or UHS-3 | not on product pages | not on product pages |
| DJI Osmo Action 6, Osmo Action 5 Pro | U3, V30 on recommended list | exFAT | 1TB |
Swipe for 1 more column →
Sources: Insta360 online manuals, GoPro product pages and DJI spec pages (checked Sep 30, 2026).
◆ Key finding
No manufacturer here asks for more than V30, and Insta360 steers X6 buyers away from V60 and V90 cards.
The Insta360 GO Ultra is where Insta360 contradicts itself. Its storage page and a hardware spec page say "up to 2TB," while its first-use tutorial warns that "memory cards exceeding 1TB may be incompatible." We list 2TB as the published spec. I'd still buy 1TB or smaller, the size both pages accept.
SD Card for Insta360 X5, X4 and X3
One rule covers an SD card for Insta360 cameras with a slot. Buy UHS-I, V30 or higher and 1TB or under. Moving from the Insta360 X3 to the Insta360 X5 doesn't mean new cards, since both manuals ask for the same spec. The X5 troubleshooting page adds a size floor. It says 32GB and 64GB cards "are more likely to trigger insufficient speed warnings" and recommends 128GB or larger.
Insta360's blog, updated June 22, 2026, asks for a "minimum 120MB/s write speed" for continuous 8K video. Its manuals ask for V30, a 30MB/s floor. We use the manuals, because they're model-specific and 120MB/s matches no speed class the SD Association defines.
GoPro and DJI Card Requirements
GoPro keeps its requirement to a footnote. The HERO13 Black and MISSION 1 product pages both say "MicroSD card rating v30 or UHS-3," and that line is the whole spec for a micro SD card for GoPro cameras on those pages. Neither lists a maximum capacity.
The MISSION 1 page does list a maximum video bitrate of 240Mbps, or 30MB/s, exactly the V30 floor. GoPro says GoPro Labs can "push it even further," past anything a V30 card promises.
DJI publishes more. The Osmo Action 6 and Osmo Action 5 Pro spec pages list "microSD (up to 1 TB)," exFAT and a maximum video bitrate of 120Mbps. US availability for the Osmo Action 6 shifts between DJI's official store and third-party retailers, so check it before you buy.
Cameras With Built-In Storage
The Insta360 GO 3S has 64GB or 128GB built in and no card slot, so the capacity you pick at checkout is the one you keep. Three cameras here have both. The X6 and Osmo Action 5 Pro carry 64GB (47GB usable), and the Osmo Action 6 has 64GB (50GB usable). A card takes you past that.
SD Card for 4K Video: Match the Card to the Bitrate
Picking an SD card for 4K video comes down to one conversion. Cameras publish bitrate in megabits per second (Mbps), cards publish speed in megabytes per second (MB/s), and a byte is eight bits. Divide by eight.
DJI's 120Mbps maximum is 15MB/s, half the V30 floor, and Insta360 lists the same 120Mbps as the Ace Pro 2's High bitrate. Insta360 publishes no bitrate for the X4, only 1.5GB per minute at 8K30 High, which by our calculation is about 25MB/s (roughly 200Mbps).
When a card falls behind, the camera stops recording or throws what the X5 manual calls "insufficient speed warnings." Higher-bitrate modes also fill a card faster, so your resolution and frame-rate settings decide how long a card lasts as much as its capacity does.
How Much Video Can 128GB Hold?
A 128GB card holds roughly 2 hours 20 minutes of 120Mbps video. We calculated the table from label capacity and per-minute figures, rounded to five minutes. The 120Mbps column uses Insta360's 900MB per minute for the Ace Pro 2's High setting, and the X4 columns use the figures Insta360 publishes for the Insta360 X4.
| Card | 120Mbps (about 900MB/min) | X4 8K30 High (1.5GB/min) | X4 5.7K30 High (700MB/min) |
|---|---|---|---|
| 128GB | 2 hr 20 min | 1 hr 25 min | 3 hr 5 min |
| 256GB | 4 hr 45 min | 2 hr 50 min | 6 hr 5 min |
| 512GB | 9 hr 30 min | 5 hr 40 min | 12 hr 10 min |
| 1TB | 18 hr 30 min | 11 hr 5 min | 23 hr 50 min |
Swipe for 1 more column →
Source: Insta360 per-minute figures (checked Sep 30, 2026).
How much video can 256GB hold? About 4 hours 45 minutes at 120Mbps. Real totals run a little lower, because a card formats to slightly less than its label and Insta360 tells X4 owners to leave 1–2GB of reserve space for recording cache. Long clips also split into segments of up to 29 minutes 59 seconds on the Ace Pro 2.
exFAT vs FAT32 on an Action Camera Card
On a camera card, capacity settles exFAT vs FAT32 for you. The SDXC standard covers cards over 32GB up to 2TB using exFAT, while SDHC cards from over 2GB to 32GB use FAT32. Every card from 64GB to 2TB is SDXC.
FAT32 caps a single file at 4GB, which fills in under five minutes at 120Mbps. Older cameras on small cards split long recordings into chapters for that reason. Insta360 requires exFAT on every current model with a slot, and the X4 manual says that on a computer "the allocation unit size should be set to default."
How to Format a Micro SD Card for an Action Camera
Format each card in the camera that will use it, including after a swap between cameras.
◆ Warning
Formatting erases everything on the card. Insta360's Ace Pro 2 manual states that deleted files cannot be recovered.
Formatting in the Camera
- Copy everything you want to keep onto a computer or drive.
- Insert the card and power the camera on.
- Open the storage settings. On the X4, swipe down and tap Settings > SD Card > Format, or use Settings > Other Settings > Camera Storage > Format Storage in the Insta360 App.
- Confirm, then record a short test clip and play it back.
If an X4, X4 Air or X5 keeps throwing card-speed warnings after that, Insta360's troubleshooting page offers "Low-Level Format" as the next fix.
Formatting on a Computer
The SD Association strongly recommends its SD Memory Card Formatter over "formatting tools provided with individual operating systems." Choose exFAT at the default allocation size, then format again in the camera so it builds its own folders.
Footage often survives a flood when the camera doesn't, which is why the first minute with a water-damaged action camera means pulling the battery and then the card.
What Manufacturers Don't Publish
GoPro's product pages give no card capacity limit, and the HERO13 Black page gives no bitrate. The Insta360 X5, X6 and GO Ultra pages we checked give no per-minute storage or maximum bitrate. No manufacturer publishes a sustained-write test of the cards on its own recommended list, so those lists show compatibility and say nothing about measured speed.
Frequently asked questions
Is U3 or V30 Better?
U3 and V30 are equal on speed, because both promise a minimum sequential write of 30MB/s. V30 is the Video Speed Class label, the one Insta360 and DJI name, while GoPro's footnote accepts either. Buy a card that prints both symbols and the choice stops mattering.
Is a V30 SD Card Good for 4K?
Yes, a V30 SD card is good for 4K, because its 30MB/s floor covers video up to 240Mbps. DJI's highest published bitrate is 120Mbps, and Insta360 lists 120Mbps as the Ace Pro 2's High setting. The tight case is GoPro's MISSION 1, whose 240Mbps maximum uses the whole floor.
What Does It Mean to Format an SD Card?
Formatting an SD card means rebuilding its file system and wiping the index of everything stored on it, so the card starts empty. When you format in the camera, the camera also writes the folder structure it expects. Always copy your footage off first, since a format clears every file on the card.
What Are the Disadvantages of exFAT?
The main disadvantage of exFAT is compatibility. Some older computers, TVs, car stereos and cameras can't read it, while FAT32 works on almost anything. exFAT also keeps no journal, so pulling a card mid-write can leave files damaged. For a card that lives in a current action camera, neither point changes the choice.
How Do You Test SD Card Speed?
To test SD card speed, run a full-capacity write-and-verify test on a computer, then compare the sustained write figure with the card's V rating. Filling the whole card matters because counterfeit cards can report a fake capacity and fail once data passes the real limit. A card that falls below 30MB/s sustained goes back.
Buy the Class Your Manual Names, Then Format It in the Camera
The packet sells the read speed, and the manual names the write floor. For a micro SD card for action camera recording, go by the manual, then let the camera format the card before the first clip.
Two of the four picks in the best action camera ranking change the card math. The Osmo Action 5 Pro has 47GB usable built in, and the MISSION 1's 240Mbps uses every bit of a V30 card's floor.