microSD and SD Card Buying Guide: Speed Classes & What to Buy

That 512GB link for me (in the UK) is well over £100 (4.67GB per £)* - I had made my quick judgement (my apologies) based on that compared to Sandisk's Ultra 400GB (5.48GB per £) though I now see that they can be had noticeably cheaper - https://www.amazon.co.uk/Lexar-High...micro+sdhc&qid=1598392104&s=computers&sr=1-26 (ie 5.76GB per £) which is definitely better than the given link though I'll probably go for the Sandisk given that it's down to £48.99, or 8.16GB per £, in their sale (£15.99 for a Sandisk Ultra 128GB). I did see though that the Lexar might actually be as fast as the Sandisk Extreme
*thanks to taxes, I normally look at USD as equalling GBP - sad times.
It's showing $32.99 USD for me, for the 512G Lexar. Several other cards are going for under $40 US for 512G including the SanDisk Extreme.
I had micro SD malfunction fairly often back when phones still had them.
That is my primary reason I do not miss much not having micro sd cards in phones.
I never had any problems with SD cards though using them in cameras.
I wonder if from technological standpoint there is a noticeable difference between them.
This is a great overview of (micro) SD cards.
I'd like to see if what the marketing *says* the card does is what the actually *can* do.
I tend to have little faith in SD cards marketing.

Would you consider doing an actual test on some of these and showing us that they actually meet their stated speeds?
You forgot high-endurance cards. High-endurance cards are good for e.g. Tesla automobile continuous monitoring or dashboard recording of all driving events in case of a crash or other video surveillance continuous-use cases. High endurance cards are often MLC (2-bit NAND flash) so they are 3x-5x more durable than TLC flash. I like SanDisk MAX Endurance cards, with a 3 year expected life(32GB) up to 15 years expected life (256GB), the High Endurance only have a 2-year expected life for continuous writing cycles.
The majority of HE cards primarily utilize 3D TLC NAND flash, ensuring sufficient endurance. Even in the case of large SD cards, the utilization of memory chips remains limited, thus the level of over-provisioning is not notably excessive.