SanDisk 64GB Extreme microSDXC UHS-I Memory Card with Adapter - Up to 160MB/s, C10, U3, V30, 4K, A2, Micro SD - SDSQXA2-064G-GN6MA

This is one of the fastest traditional MicroSD cards on the market if not THE fastest and performs great at a lot of tasks. I use this in my Asus ROG Ally X(the updated one that doesn't cook MicroSDs) and it is more than enough for emulation up to PS3 as well as older PC games. This is a great way to expand my Ally X's storage without needing an even more expensive SSD than I've already put in it. That it's removable makes it infinitely useful for transferring material from my main PC.I cannot speak for its speed for other uses, however it is the fastest MicroSD card I've ever owned by far. Pretty expensive for the capacity and speed but there is literally almost nothing better for this specific application. Good stuff!

Great quality. Fast speed.

Fantastic choice for my Steam Deck. The memory is fast, and a good value. It's reliable, and I've had no issues with it.

High speed, high capacity. Works exactly as advertised. The packaging was easy to get into. Nothing else to say!

Great product. I discovered that it is not always the memory size but in some cases like my video doorbell, you need speed as well. Be sure to check speed requirement before you waste your money on a memory card. Not all are created equal. This card works awesome for my application.

I haven't had good luck with Sandisk micro SD cards. I haven't had any failures but these are my two issues:1. On large file transfers - more than 1gb - Sandisk tends to overheat and lose transfer speed. This is worse writing TO the card than reading from it. Transfer speeds are stil ok, but nothing like the speeds I get from my USB 3.1 port with a thumbdrive. Several years ago the problem was so severe my files got corrupted even when the on-board thermal protection was throttling my transfer speeds down to 5-10 megabytes per second. In the past two years data loss has ceased to be a problem, and the speed hit on large file transfers is much less severe, although Samsung continues to run faster, in real life big file transfers, than San Disk, at least for me.2. I don't think Sandisk really meets the specs required for "extendable" or "unified" storage on Android, that or it throttles so early the perfomance on small, constant file reads and writes suffers more than it should. I almost always get an error message with their A1 cards on budget (Qualcom 42x chipset) phones complaining the storage is slow and hence not optimal as unified storage. I haven't gotten this error message with my two Fire HD 10 9th gen tablets on this latest A2 iteration, however, which may be a function of the chipsets and memory controller used in these tablets or maybe the upgrade from A1 to A2 makes a difference.I purchased two Fire HD 10's, 2020 editions/9th gen (the second one purchased on Prime Day for just $80, which is insanely cheap) and two of these A2 class Sandisk 128gb micro SD cards.A2 means the memory controller built into the micro SD card should be fast enough to run apps (not gaming apps!) from the card, not just read storage data.The real challenge is for app-rated (A1 or A2) card to handle data reads and writes for multiple apps at the same time. "Same time" is critical - it's not reading a single big file that creates problems for micro SD cards, it's reading small files at nearly the same time to handle the needs of multiple apps running at the same time. The way to avoid any performance issues is to NOT allow the operating system to "move" apps from true internal storage to the SD card. Only data.The first 128gb drive installed perfectly easily in my first Fire as "portable" or "removable" storage but that is not surprising. The second card was installed as "internal storage" in the second Fire glitched several times, crashing once, and not recognized by the tablet as storage at all. I don't know what I finally did to get past the glitches. but as far as I can tell what finally worked was first formatting it as "portable" storage first, rthen ebooting, then re-formatting it as "internal" storage.I was "offered" a chance to move some apps onto the SD card after formatting as internal storage. DO NOT do this - the 32gb of internal, faster storage is a much better place to run apps from, not the SD card even though it is A2 "app-friendly" classified. All CONTENT will automatically go to the SD card in the future, such as downloaded Netflix and Prime Videos.Pay attention to the following issues which might develop:1. Simultaneously downloading videos or other content AND watching a previously stored video. This can tax the memory controller in the SD card since essentially the device is attempting to read your video and write your downloading episodes at the same time (subject to buffering). It shouldn't be a problem,but it might. I usually download content when I'm not using the tablet.2. Moving lots of content from external storage - like a thumb drive - to internal storage. The process is ALWAYS a lot faster going from USB 3 thumbdrives to internal factory storage, and slower when writing to the SD card.In my review title I mentioned I prefer Samsung. Without doubt they make more dependable SD cards that more consistently "hit" their specs and don't throttle down as much on large file transfers. However, Sandisk pretty much "owns" the A1 and A2 "app friendly" micro SD space, and they frequently go on sale. Since they no longer "corrupt" large file transfers (I'm talking about moving a 30gb music collection to an SD card in a computer, not just a couple of gb), I no longer avoid Sandisk like the plague. Still, as they say, once burned twice wary.I'm hunting for reviews from Raspberry Pi users. Running an actual operating system from a micro SD card is equally hard, or harder, than running Android apps. So far, the micro SD cards recommend for those Raspberry Pi systems are NOT A1 or A2 class or even necessarily "faster" micro SD cards - apparently speed on larger files doesn't necessarily correlate to the speed required for smaller, constant file transfers that an operating system needs.It's good to see micro SD card prices become so low and commodity-like. I can remember when cards were a dollar a gigabyte, or much more. For under $20 I'm more than willing to give this Sandisk A2 128gb micro SD card a workout in my Fire HD 10 9th gen.I'm also a little surprised to see all the new brand names. I'm used more to Samsung and Sandisk at the top, with Kensington, Patriot, etc. as the next tier. My guess is Chinese subcontractor factories feel less bound to have a long-standing brand name and are just going direct to market. Time will tell how this works out for consumers.

Fast speeds.Always reads and writes no problem so very easy to useAdapter works good and works in my GoPro's and DJI cameras/ drones.The price fluctuates so when it drops I buy more.

Works great, good writing and reading speeds, perfect to expand storage on a tablet.