Choosing the Best Memory Card: Card Speed and Compatibility Guide for UK Users

Understanding Memory Card Formats in 2026

The memory card market has three dominant formats right now: SD, microSD, and CFexpress. Each serves different devices, and picking the wrong one means either wasted money or — worse — dropped frames and corrupted files. I've been through that pain myself, losing a full day's footage from a drone flight over Belfast Lough because I'd cheaped out on a no-name microSD that couldn't keep up.

So what's actually different between them?

SD (Secure Digital)

The full-size SD card measures 32mm × 24mm × 2.1mm. It's the standard for DSLRs, mirrorless cameras, and older laptops. Current SDXC cards top out at 2TB capacity, though most folk are buying between 128GB and 512GB.

microSD

Physically tiny at 15mm × 11mm × 1mm. Same underlying tech as SD but built for smartphones, drones, action cameras, and the Nintendo Switch. You can use a microSD in a full-size SD slot with an adapter — dead handy if you're switching between devices.

CFexpress

The professional's choice. CFexpress Type B cards deliver read speeds up to 4,000 MB/s. They're physically larger (38.5mm × 29.8mm × 3.8mm) and significantly pricier — expect £150–£400 for a 256GB card. Type A is smaller and used primarily in Sony bodies.

There's also CompactFlash (the old square format) still kicking about in legacy DSLRs. For anything purchased after 2020, though, you're looking at one of the three above.

Speed Classes Explained: What the Numbers Actually Mean

Speed ratings on storage cards are genuinely confusing. There are at least four different classification systems printed on a single card. Here's what each one tells you.

Speed Class (C2, C4, C6, C10)

The number inside the "C" symbol represents minimum sustained write speed in MB/s. A Class 10 card guarantees at least 10 MB/s sequential write. Honestly, anything below C10 is obsolete for modern use — don't bother.

UHS Speed Class (U1, U3)

U1 guarantees 10 MB/s minimum write; U3 guarantees 30 MB/s. For 4K video recording, U3 is the baseline. U1 cards are fine for basic photography, but the price difference is so small now (often under £3) that there's no reason not to go U3.

Video Speed Class (V30, V60, V90)

This is the one that matters most for videographers. The number directly states minimum sustained write speed: V30 = 30 MB/s, V60 = 60 MB/s, V90 = 90 MB/s. For 8K recording or high-bitrate 4K at 120fps, you'll want V60 minimum.

Application Performance Class (A1, A2)

Relevant for smartphones and the Steam Deck. A1 handles 1,500 random read IOPS and 500 write IOPS. A2 bumps that to 4,000 read and 2,000 write IOPS. If you're running apps directly from the card, A2 makes a noticeable difference — and the price gap between A1 and A2 has narrowed to almost nothing in 2026, so there's little excuse not to go for it., a favourite among Britain’s tradespeople

Memory Card Selection for Cameras

Your camera's manual will list compatible formats, but here's the practical reality for popular systems available in the UK this spring.

Mirrorless Cameras (Sony, Canon, Nikon)

Most mid-range mirrorless bodies from 2023 onwards use SD UHS-II slots. The Canon R6 Mark III, Nikon Z6 III, and Sony A7 IV all accept UHS-II SD cards with bus speeds up to 312 MB/s. That's plenty for 4K/60p recording in most codecs.

Professional bodies like the Canon R5 II and Nikon Z8 use CFexpress Type B. If you're shooting 8K RAW internally, you'll need a CFexpress card rated at minimum 1,400 MB/s write speed. The Samsung PRO Plus range offers brilliant reliability for SD-based cameras, and I've used them extensively without a single write error.

Compact and Bridge Cameras

These typically use standard SDXC cards. A 128GB V30 card will run you about £12–£18 and last ages for casual shooting. No need to overspend here.

GoPro and DJI Action Cameras

microSD only. GoPro's official compatibility list is strict — they recommend specific models from SanDisk, Samsung, and Lexar. A GoPro Hero 13 Black recording 5.3K/60fps needs a V30/A2 microSD at minimum. I'd recommend 256GB as the sweet spot: enough for a full day's shooting without swapping cards.

Drones and Action Cameras: What You Need

Drone storage requirements have jumped significantly since 2024. The DJI Air 3S records 4K/100fps, which demands sustained write speeds the cheap cards simply can't deliver.

Here's what I've learned from flying around the Belfast coastline: temperature matters. On cold mornings (we get plenty of those), some microSD cards slow down noticeably. Samsung's EVO Plus and PRO Plus lines handle temperatures from -25°C to 85°C, which covers anything the UK weather throws at you.

Minimum Specs for Popular Drones (2026)

Worth the extra spend on a higher-rated card? Absolutely. A V60 microSD costs maybe £8–£12 more than a V30 in the 256GB size, and it gives you headroom for firmware updates that might increase bitrates. My mate swears by the Lexar Professional 1066x for his Mavic — decent speeds and he's never had a mid-flight write failure.

One thing to watch: the Which? consumer reviews regularly flag counterfeit memory cards sold through marketplace sellers. If the price looks too good, it probably is. Stick to authorised UK retailers.

Gaming Console Storage: PS5, Switch, and Steam Deck

Gaming is where the memory card format choice gets interesting, because each console has different requirements and limitations.

Nintendo Switch / Switch 2

The Switch uses microSD (SDXC compatible, up to 2TB). Game sizes range from 1GB to 32GB typically, so a 256GB card holds roughly 10–15 major titles. The Switch's bus maxes out at UHS-I speeds (104 MB/s), so there's zero benefit paying extra for UHS-II cards — they'll work but won't run any faster.

For the Switch 2 launching this year, early specs suggest UHS-II support. If you're buying now with the Switch 2 in mind, a UHS-II A2 card is a sensible future-proof choice. (Whether you'll actually need that headroom on day one is another question, but it won't hurt.)

Steam Deck / ROG Ally

These handhelds use microSD with UHS-I interface (Steam Deck) or UHS-II (ROG Ally X). An A2-rated card makes a real difference to game load times here. I tested a Samsung EVO Select A2 512GB against a generic A1 card — load times dropped by 15–20% on average across five games.

PlayStation 5

The PS5 doesn't use memory cards at all — it takes M.2 NVMe SSDs for expansion. If that's what you're after, Samsung's 990 Pro range at nvmix.co.uk is spot on for PS5 compatibility with read speeds hitting 7,450 MB/s.

Memory Card Format Comparison Table

This table covers the main formats you'll encounter when shopping for a memory card in the UK market as of June 2026.

Prices reflect UK retail as of spring 2026. You'll find competitive pricing on nvmix.co.uk across all major brands including Samsung, Crucial, and Kingston.

UK Buying Tips and Avoiding Common Mistakes

A few things I've picked up over the years that save headaches — and money.

Counterfeits Are Rampant

UK trading standards authorities have flagged memory card counterfeiting as a growing issue. Fake cards often report incorrect capacities — a card labelled 512GB might only have 32GB of actual NAND flash, with data silently corrupting once you exceed that. Buy from authorised retailers. Trading Standards maintains guidance on spotting counterfeit electronics., popular across England

Don't Overspend on Speed You Can't Use

If your device has a UHS-I bus, a UHS-II card won't perform any faster in that device. You're paying for speed the hardware physically can't access. Check your device specs first.

Capacity Sweet Spots

Right now in the UK market, 256GB offers the best price-per-gigabyte for both SD and microSD formats. The 512GB tier is catching up but still carries a 15–20% premium per GB. 1TB cards exist but cost roughly 3× what two 512GB cards would — only worth it if you genuinely can't swap mid-session.

Warranty and Data Recovery

Samsung and Crucial both offer limited lifetime warranties on their consumer SD cards in the UK. That's peace of mind if a card fails within its rated endurance. SanDisk offers 30 years on their Extreme Pro line. Keep your receipts — UK consumer law under the Consumer Rights Act 2015 gives you additional protections for goods that don't last a reasonable time.

Look, I know it's tempting to grab the cheapest option on a marketplace listing. But I've seen too many people lose irreplaceable photos and footage to dodgy cards. Spend the extra few quid on a reputable brand from a proper retailer. You'll thank yourself later.

Key Takeaways

• Match the format to your device: SD for cameras, microSD for drones/consoles/phones, CFexpress for professional 8K workflows.
• V30 is the 2026 baseline for any video-capable device — don't buy below this speed class for cameras or drones.
• 256GB is the UK price sweet spot across all formats, offering the best cost-per-gigabyte in spring 2026.
• UHS-II only helps if your device supports it — check your hardware's bus speed before paying the premium.
• A2-rated microSD cards deliver measurably faster game loads on Steam Deck and Switch 2 versus A1 cards.
• Buy from authorised UK retailers only — counterfeit memory card products are widespread on marketplace platforms and can cause data loss.
• Keep your receipt: UK consumer law and manufacturer warranties (up to lifetime on Samsung/Crucial) protect you if cards fail prematurely.