Aura HD Micro SD Card - All about Classes

[xibalban]

Hey folks,

I'm a "soon-to-be" proud owner of a Kobo Aura HD, which I've ordered from the Kobo website. I intend to fill the device with a lot of PDFs, ePubs and CBR(Z)s; I really mean "a lot".

The device has a micro SD slot and I am planning to buy a 32 GB card. I discovered that there are many classes viz class 2, 4, 6 & 10 of SD cards. The class 10 card, they say, is the fastest. I'd like a fast card, really. Nonetheless, I read somewhere that class 10 cards are best for smartphones and to transfer/play large sized multimedia like HD videos. When it comes to smaller chunks of files - the class 4 outdoes even the class 10 cards. I've also read that the host device (Aura HD in my case) restricts the full potential of a card. Can the Aura HD host class 10 cards?

I was thinking of buying a 32 GB SanDisk Ultra (Class 10) card from a local store. My CBR(Z) and PDF files would be in average sizes of 30 MB & 100 MB respectively.

Comments/advice please!

[Ken Maltby]

The Samsung and SanDisk class 10 cards still have good small file performance, some of the other brands have optimized their larger file performance at the expense of the smaller file performance.

You might want to consider the Koreader alternative reader program, especially for PDF and CBR reading. An install guide. With a large library you might also want to hide your book files from Kobo's processing, (discussed in the guide).

Luck;
Ken

[xibalban]

Originally Posted by Ken Maltby

The Samsung and SanDisk class 10 cards still have good small file performance, some of the other brands have optimized their larger file performance at the expense of the smaller file performance.

You might want to consider the Koreader alternative reader program, especially for PDF and CBR reading. An install guide. With a large library you might also want to hide your book files from Kobo's processing, (discussed in the guide).

Luck;
Ken

Thanks! I'm a tad confused about "small" files' definition. Small implies less than 100 MB, maybe?

About KoReader, I felt that with an upgrade to firmware 3.8.0, the stock experience would be good enough. Or will it no be?

[Ken Maltby]

Originally Posted by xibalban

Thanks! I'm a tad confused about "small" files' definition. Small implies less than 100 MB, maybe?

About KoReader, I felt that with an upgrade to firmware 3.8.0, the stock experience would be good enough. Or will it no be?

Not sure what sizes were used in the testing but it is in relation to large multimedia files.

Adding Koreader does not remove or disable the stock readers. See for yourself which you prefer, especially for PDFs. I no longer use the stock readers, for a number of reasons, but I have both those and Coolreader and Koreader available to use as I wish.

Luck;
Ken

[DNSB]

Originally Posted by xibalban

Thanks! I'm a tad confused about "small" files' definition. Small implies less than 100 MB, maybe?

About KoReader, I felt that with an upgrade to firmware 3.8.0, the stock experience would be good enough. Or will it no be?

Koreader does offer some benefits for pdf files. Personally, I mostly read epubs and use the Kobo supplied software for that. Occasionally when I need to read some of the pdf manuals I have on my Aura HD, I use Koreader.

Small files varies depending on whom you talk to. The program I use for testing SD card performance on my Windows laptop is CrystalDiskMark. It has 4 performance tests. Sequential, 512KB, 4K and 4K QD32. For the most part, the performance with Sequential is best followed by 512KB. The 4K block size tests are useful for when you will be running a Linux/Android/whatever operating system which often read and write data in small chunks scattered over the storage medium. Useful when I was replacing the internal uSD card and wanted to keep the best performance.

For your purposes, any reputable card manufacturer would do though as Ken mentioned, SanDisk and Samsung seem to have the best small block performance even on their higher speed/larger capacity cards.

The other item to keep an eye on is the possibility of being sold a counterfeit card. I purchased two uSD cards which were supposedly Kingston 32GB cards. One of them failed when I attempted to copy a batch of video files which ran about 3GB each -- old film noir movies such as D.O.A. from the Internet Archive. When I ran the H2testw program on them, it reported them as 3.8GB cards not the 29.6GB which Windows reported them as being. And this was cards purchased from a local and fairly reputable shop.

Regards,
David

[JimMcLaren]

Originally Posted by xibalban

About KoReader, I felt that with an upgrade to firmware 3.8.0, the stock experience would be good enough. Or will it no be?

I've tried to love the Kobo software. I really did. It has a couple of features that koreader does not, notably automatically going to sleep after a period of time. For PDFs I would crop them with k2pdf and the reading experience is reasonable. Since koreader does almost exactly the same thing as k2pdf, but on the fly, I eventually came back to koreader. Like Ken said, you can go back and forth.

[DNSB]

Originally Posted by JimMcLaren

I've tried to love the Kobo software. I really did. It has a couple of features that koreader does not, notably automatically going to sleep after a period of time. For PDFs I would crop them with k2pdf and the reading experience is reasonable. Since koreader does almost exactly the same thing as k2pdf, but on the fly, I eventually came back to koreader. Like Ken said, you can go back and forth.

The nice part is that we don't have make an exclusive choice. I spend most of my time reading epubs so the Kobo/RMSDK renderer works for me. When I do need to read a pdf file (mostly tech manuals), a quick reboot to use koreader works. I prefer epubs for my personal reading since Sigil or Calibre's built-in editor makes editing them quite painless.

Now if they made a 28" eInk screen (~4500x6000 pixels) so I could bring up a A3 sized diagram at a readable size without needing to scroll a window around the page....

Regards,

David

[EndlessWaves]

The SD class system allows manufacturers to specify a minimum supported speed for streaming writes (recording video). They don't denote different devices and only have limited relevance for types of data transfer.