Collection: SD Memory Card

Which SD memory card do you actually need?

Most PC builders spend hours agonising over Desktop Memory timings and then grab whatever SD memory card is next to the checkout. That works until a camera drops frames or a handheld stutters. Under the hood, the difference between tiers is mostly about sustained write speed, not the headline number on the label.

Entry cards, such as SanDisk Ultra or Kingston Canvas Select Plus, are UHS-I devices capped around 100MB/s reads. They typically use a simple controller and TLC or QLC NAND with limited write caching. They suit dashcams, Switch-style handhelds, Raspberry Pi projects and general storage. The sweet spot is a UHS-I V30 card like the SanDisk Extreme, Samsung PRO Plus or Lexar Professional Silver. These have a guaranteed minimum sustained write of 30MB/s, so 4K video and burst photography don't stall when the cache fills. Enthusiast cards are UHS-II V60 or V90, like the SanDisk Extreme PRO UHS-II, ProGrade Digital Gold and Angelbird AV PRO. They add a second row of pins and a wider interface, with reads over 250MB/s and sustained writes of 90MB/s or more. They need higher-grade NAND and better thermal design, which is why they cost much more.

Diminishing returns hit hard after V30 unless you shoot high-bitrate raw video or large raw burst sequences. A UHS-II card in a UHS-I device just runs as UHS-I, so you've paid for speed you can't use.

Upgrading and technical nuances

The speed class labels are easy to misread. U3 and V30 both promise 30MB/s minimum sustained writes, while the large "170MB/s" figure is a best-case burst read. A1 and A2 ratings cover random IOPS, which matters if you run apps or a game library from the card, such as on a handheld. A2 cards need host support for command queuing to hit their ratings, and some readers and older devices ignore it.

Capacity standards are another trap. SDHC covers up to 32GB and uses FAT32. SDXC covers 64GB to 2TB and ships formatted as exFAT. Older cameras and car stereos may not read exFAT at all, so check before buying a 512GB card for an old device. SDUC goes beyond 2TB but is rare in practice.

SD Express is the newer architecture. It runs over PCIe and NVMe rather than the legacy UHS bus, which gives SSD-like speeds in a microSD or full-size form. It needs a compatible host and reader, and today the supporting hardware is limited. Unless your device explicitly lists SD Express, don't pay a premium for it.

On the PC side, most current Motherboards for AM5 and LGA1851 don't include an SD slot, and those that do are often UHS-I only. A laptop slot is usually the same. For fast UHS-II transfers you want a dedicated USB 3.2 reader. If your workflow is moving hundreds of gigabytes, offloading to a Solid State Drive (SSD) such as a Samsung 990 or Crucial T500 is worth planning for, because the card is the slow link in the chain.

Practical things to check

Start with the host device. Check the maximum supported capacity, the supported file system and whether it has UHS-II pins. Many mirrorless bodies have one UHS-II slot and one UHS-I slot, so the second card will be the bottleneck in dual-slot recording.

Heat matters more than people expect. High-end cards throttle under long 4K or 8K recording sessions, and write speeds can drop when the controller gets hot. Keep cameras ventilated, and avoid leaving cards in a hot car. The same applies to readers: a cheap reader on a warm desk will drop speeds. Keep it away from a hot GPU exhaust. If your build is cramped, good airflow from Computer Cases and Fans, Heatsinks & Cooling helps keep front-panel readers from soaking up heat.

The reader and cable are the bottleneck more often than the card. A UHS-II card in a UHS-I reader gives you roughly one third of its potential speed. Use a reader with a proper USB 3.2 Gen 2 link, and use the short cable it came with. If you need to extend it, a quality option from Cables & Connectors is better than a random cheap lead. Plug it into a rear motherboard port rather than an unpowered hub.

Also check the physical card. A full-size SD card has a write-protect slider that can accidentally engage and make the card read-only. If you want microSD, make sure you get the adaptor and don't assume it supports UHS-II, because most adaptors only pass UHS-I signals.

Finally, test new cards on arrival. Tools like H2testw or F3 can expose counterfeit capacity within minutes. Fake cards are common on marketplace sites, and the faster the card claims to be, the more tempting it is to counterfeit.

Brands and local warranty

SanDisk (Western Digital), Samsung, Lexar, Kingston, ProGrade Digital, Angelbird and Delkin are the main names worth shopping. SanDisk Extreme and Extreme PRO are the safe defaults for photographers and videographers. Samsung PRO Plus and EVO Select are strong all-rounders and good value for everyday use. Lexar Professional covers both budget and UHS-II tiers. ProGrade and Angelbird focus on professional workflows, with tighter validation and consistent sustained speeds. Kingston Canvas is an honest budget option when you need volume.

Genuine Australian warranty support matters more for memory cards than most people think. Many cards are lifetime-warranted, but that only helps if the retailer sources local stock and handles claims properly. Grey imports and marketplace sellers can ship counterfeit or unsupported units, and manufacturers may refuse claims for them. Buying from a local retailer means a replacement process under Australian Consumer Law, without having to ship offshore. If the card holds client work, that's worth far more than the few dollars you might save.

If you're also building out a wider workflow, a decent Computers setup, a good Monitors panel for colour-accurate editing and solid Networking gear from TP-Link for moving files to a NAS will all matter as much as the card.

Frequently asked questions

Is a UHS-II card worth it if my device is UHS-I?

No. It will run at UHS-I speeds, so you're paying for performance you can't use. The one exception is if you plan to upgrade your camera or reader soon, and even then a V30 card is the better balance today.

What capacity should I buy?

For stills, 64GB to 128GB is plenty. For 4K video, go 256GB or higher, since bitrates chew through space. Multiple mid-sized cards are safer than one huge one, because a single card failure won't take everything with it.

What do V30, U3 and A2 actually mean?

V30 and U3 both guarantee a minimum sustained write speed of 30MB/s, which is what video recording needs. A2 refers to random read and write performance for running apps or games from the card. They measure different things, so check which one your use case needs.

Can I use an SD card as game storage on a handheld?

Yes, but pick a quality A2-rated card from a reputable brand like Samsung or SanDisk. Random performance affects load times, and cheap cards can stutter and wear out sooner.

How do I know if a card is fake?

Buy from a trusted local retailer, then test the full capacity with H2testw or F3. If the usable capacity is lower than advertised or write speeds collapse, return it straight away.