SanDisk 512GB microSD Express Card – Works with Nintendo-Switch 2, Up to 880MB/s Read, Up to 650MB/s Write, 220MB/s Sustained Write, U3, C10 – SDSQXFN-512G-GN4N

With over 1GB/s file transfer performance, this card is still the best on the market
Update 06/07/2025, Comparing to Onn’s Express 256:There is a new budget microSD 256 Express card from Onn that appeared in retail this week coinciding with the launch of the Switch 2. It claims to support up to 800MB/s reads and 600MB/s writes. I picked one up to compare. With larger stress tests (Random reads and writes going up to 5GB instead of the 1GB test I show here), this SanDisk can see its transfer rate drop to a minimum of 400GB/s on writes. For the Onn device, on writes the rate drops to 200MB/s typically, but sometimes as low as 150MB/s as the firmware seems to have trouble keeping up (it stalls completely), nearly 3 times slower on average than the SanDisk. What’s worse is that it drops to 400GB/s even for transfers as small as 2GB, 300GB/s for 3GB, and 200GB/s from there on up, while the SanDisk still manages to hold minimum 600GB/s. Keep in mind that most larger games for the Switch 2 are about 20GB or more, and there are a few 64GB or larger. I do not currently own a PNY card to test, but online evidence suggests that it too is slower than the SanDisk, but may be faster than the Onn device. With the way the Onn card stalls on writing, literally stopping occasionally for upwards of a second while testing, I could never recommend it. You get what you pay for with the SanDisk. Full review follows.REVIEW:During play, the Onn express card may be able to keep up due to small transfers and minimal loads, but its stalls will affect things, and during download and game management on the Switch 2, you will definitely see a time impact, probably significant. The good news is that the Onn express card was able to hold up on read tests without stalls, with the same 750MB/s as the SanDisk, but it never really went above 750MB/s for even smaller transfers while the Sandisk peaked at about 990MB/s, above their claimed rate. I am sure some caching was involved in that number, but the system caches the Onn in the same way, so there is a significant difference.Great high-speed card if you have a reader that supports Express. This card also outperforms even on a standard controller due to its rapid response time and excellent IOPs (measure of the number it can handle per second). Does well enough to be considered as an external drive on the Mac, though an M.2 reader enclosure will outperform it on specs. Can’t beat it for portability.For sustained throughput on the SanDisk Express reader, this can’t be beat, easily outperforming any other card I have from 4X to 20X faster. Camera file transfers happen at about 1GB/s. No drivers needed for any recent OS, though Ubuntu has a recent bug that will prevent those devices from attaining full speed unless an external Express-capable reader is used.

Ultra Upgrade.
I love MicroSD Cards but for 20 years the speed is now extremely slow and unusable speeds for 2TB. Now there’s MicroSD Express and the speeds are 100 times faster than 10MB per second so for that I give this 5 stars.

Rápido pero no era lo prometido
Entrega rápida aún que la memoria era de 456

Works, happy with it
Performs as expected. I had to get this to use with the Switch 2. I guess it writes faster but if so I don’t notice it compared to a non-express memory card.

Perfeito e rápido!

As intended

Switch2購入サイトで品切れのため購入。対応してたので良かった。他の使い道は未検討