SD card running slow

[aldel99]

Hi

I have 2 SD cards (samsung evo plus 256gb & 512gb) running on my S20 and Note 10+.

The advertised speed of the cards is 100 read / 90 write.

I did a couple of benchmarks and the speeds are considerably less on my phones. About 70 read and 50 write.

Is this a limitation of the phone? I bought the cards from Best Buy so I'm pretty certain they aren't knockoffs. I also had a SanDisk extreme plus in there before with advertised speeds of 170 read and 90 write and that didn't do well either in testing.

I used A1 SD BENCH and did Accurate testing (with reboot).

[Halston]

Hey aldel99,
Please provide us the model number of the Samsung Evo plus 256GB SD card. It starts with MB-. You can find it on the rear side of the SD Card.

[Vic20]

Usually hardware related. The cards (like everything else) will state theoretical speeds. It's not guaranteed... Why it's always advertised/stated as 'up to'.

[Cassidy]

I invite you to read this article to understand how it works..

https://r1.community.samsung.com/t5/others/all-about-sd-cards/m-p/2941101#M19683

If you don't have U3 V60 or more, it will give you good speed

don't expect too much on U1 class 10 card

[aldel99]

So I did se testing...
I put all 3 sd cards on my SD card reader and connected to computer. Formatted and tested with CrystalDiskMark with default settings.
All 3 cards had almost identical results for sequential read and write.
90-95 read
80-85 write

I put them back in my phones and it was back to about 75 read and 50 write

I also tried formatting the cards on my phone and not enabling encryption (I know theoretically it should make no difference but I thought I'd try it) and it made no difference