SD Card Speed Classes (A1 vs A2, U3, V30)

The call

For handhelds, the rating that actually matters is random I/O, and that means the A-class: A1 sets a floor most retro and many PC-handheld libraries never exceed, while A2 raises it — but A2’s advantage needs host support to show up, and on hardware that lacks it A2 behaves like A1 with a bigger label. U3 and V30 describe sustained sequential speed, which matters more for high-bitrate video capture than for loading games. The honest buying rule: a reputable A1 or A2 card from a known brand, sized to your library, beats chasing the top V-rating. Counterfeits are the real risk — buy from a trusted seller and verify capacity.