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Old 06-09-2025, 07:25 PM   #15
DNSB
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Posts: 46,978
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Join Date: Jul 2010
Location: Vancouver
Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos
Quote:
Originally Posted by JSWolf View Post
Has anyone tried an A2 microSD card in a Kobo and if so, has it made any noticeable speed difference?
Quote:
Originally Posted by Semwize View Post
I'm interested in that too. It seems to me that the speed will not change, except when transferring files from a computer to a device. But could be wrong, I haven't tried it)
I have. The A2 card actually slowed down my Clara HD. The higher speed might help if I am copying large ebooks to/from since that comes close to the 20 megabytes/second that the 4K video camera the card normally lives in uses. OTOH, when I ran CrystalDiskMark 8.0.6 on the card, the 4K small block read speeds were about 50% of the speed on a Class 6 SD card and the 4K write speeds were 20% of the class 6 card speed. See the attached images for the random 4K block write. Note that the likely cause for a lot of the slowness for the newer cards is that the internal block size of the card is a lot higher than 4K in the 256K to 512K size. For a 256K block size means that writing a single 4K random block results in reading a 256K block, inserting the 4K block and then re-writing the 256K block.

I've attached images of the 2 cards random 4K block writes. I do miss the sequential and random that the older CrystalDiskMark did but I can see why they removed the sequential since that ended in collecting 4K blocks and writing them in one pass.

Edit: Just for the heck of it, I attached the results for my two SSDs.
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Last edited by DNSB; 06-09-2025 at 07:47 PM.
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