Libra 2 Rev 3 Slow SD Card

[zerius]

Just wanted to share that my 2023 revision Libra 2 white came with a extremely slow internal SD card, which caused slow page turns, slower sleep and wake.

If I didn't have my wife's gen 1 libra 2 to compare, I would have just assumed it was the processing power of the device. However, upon taking the device apart and taking the SD card out - the 1st Gen Libra 2 had a SD card that was around 7x faster in RND4K writes and maybe 2x faster RND4K read vs the card that came with the 2023 revision.

I have replaced both with RASPBERRY PI SD CARD - 64GB, from Digikey, which from both synthetic benchmarks and also empirical testing, performed the quickest with sleep/wake and page turns - close seconds were the Lexar Silver Plus 64gb and the Kingston Canvas Go! 64gb. The rasperry pi card was both cheaper and faster - likely more optimized for smaller reads and writes, instead of writing 4k video.

The difference is night and day, pages turn instantly.

[DNSB]

Try doing a search in this forum for Crystaldiskmark. Or read what I think was the original discussion back in 2011 on XDA. The link is to SD Strange-results - or - How I learned to love CM7 on SD - Dec-11 results compiled!. You can also take a look at the Memory Upgrade Guide thread in Kobo Developer's Forum starting around message #16.

[JSWolf]

Originally Posted by zerius

Just wanted to share that my 2023 revision Libra 2 white came with a extremely slow internal SD card, which caused slow page turns, slower sleep and wake.

If I didn't have my wife's gen 1 libra 2 to compare, I would have just assumed it was the processing power of the device. However, upon taking the device apart and taking the SD card out - the 1st Gen Libra 2 had a SD card that was around 7x faster in RND4K writes and maybe 2x faster RND4K read vs the card that came with the 2023 revision.

I have replaced both with RASPBERRY PI SD CARD - 64GB, from Digikey, which from both synthetic benchmarks and also empirical testing, performed the quickest with sleep/wake and page turns - close seconds were the Lexar Silver Plus 64gb and the Kingston Canvas Go! 64gb. The rasperry pi card was both cheaper and faster - likely more optimized for smaller reads and writes, instead of writing 4k video.

The difference is night and day, pages turn instantly.

An A2 MicroSD card will be faster then an A1 MicroSD card. So if you don't have an A2 card, that's what you want. Watch the video and you'll see.

[DNSB]

Do you ever feel as if you are caught in a time loop?

What is important to the Kobo ereader is the small block read/write speeds. I have tested multiple cards and ones that are good for use in a video camera can stink in a Kobo ereader since the small block read/write speeds are pathetic. This topic has been discussed on MobileRead multiple times in the past. I've posted test results here and you can find multiple others around the Internet.

[Tommalka]

Rev 3? Gen 1? How do I know which revision my Libra 2 is?

[DNSB]

If you look near where the battery wires are soldered to the motherboard, you will see 37NB-E70K1M+6E0 for example. The middle character in the 3 character string after the plus sign is what we are using as the board revision (in this case, a rev E).

[Semwize]

Originally Posted by Tommalka

Rev 3? Gen 1? How do I know which revision my Libra 2 is?

NickelMenu

menu_item :main :ntx_hwconfig :cmd_spawn :quiet:/bin/ntx_hwconfig -s /dev/mmcblk0 > /mnt/onboard/ntx_output.txt

You need to look at line 42.
[42] PCB_LVL='F'

[Apollyon202]

I've just checked it again, mine is also an 'F' and the PMIC line says "BD71828" which according to this comment:
https://www.mobileread.com/forums/sh...8&postcount=49
is a revision 2. I haven't seen any clues about revision 3.

I bought my Libra 2 last year brand new from shop, and it came with factory firmware 4.34, which was installed on the 14th of September 2022.

I think the old CPU may have more of an impact on the overall responsiveness of the device than the speed of the storage.

[Semwize]

Originally Posted by Apollyon202

is a revision 2.

I don't understand why you use numbers at all.
There are 4 revisions, if I'm not mistaken.:
A,B,E,F.
That's how you should write, not invent something of your own.
I have revision 'B', and 'F' was just an example...

[Apollyon202]

I did not invent anything.
I was just referring to other posts I've seen here. Also there were only one issue on the koreader github issues page, when "a" new revision came out of the Libra 2.
https://github.com/koreader/koreader/issues/9218

Of course, that doesn't mean anything, but outside of this thread there are like zero info about the revisions and differences between Libra 2 models.
So there are possibly 4 revisions, okay. What are the differences?
Please try to answer without being an arrogant, thanks.

[Semwize]

Originally Posted by Apollyon202

So there are possibly 4 revisions, okay. What are the differences?

Spoiler:

[39] VCOM_10mV_HiByte=0xFF
[40] VCOM_10mV_LoByte=0x69
[42] PCB_LVL='A'
[44] PMIC='RC5T619'
[45] FL_PWM='LM3630'
[46] RTC='RC5T619'

[39] VCOM_10mV_HiByte=0xFF
[40] VCOM_10mV_LoByte=0x6D
[42] PCB_LVL='B'
[44] PMIC='RC5T619'
[45] FL_PWM='LM3630'
[46] RTC='RC5T619'

[39] VCOM_10mV_HiByte=0xFF
[40] VCOM_10mV_LoByte=0x6A
[42] PCB_LVL='E'
[44] PMIC='BD71828'
[45] FL_PWM='AW99703x2'
[46] RTC='BD71828'

[39] VCOM_10mV_HiByte=0xFF
[40] VCOM_10mV_LoByte=0x60
[42] PCB_LVL='F'
[44] PMIC='BD71828'
[45] FL_PWM='AW99703x2'
[46] RTC='BD71828'

I wrote that it is more correct to specify the letter, rather than writing 1,2, etc. revisions. No?

[DNSB]

Originally Posted by Apollyon202

So there are possibly 4 revisions, okay. What are the differences?
Please try to answer without being an arrogant, thanks.

As far as I am aware, most of the differences between the Libra 2 revisions have been due to chip availability. Most of the differences such as changing RAM and eMMC suppliers doesn't make much difference but the power/battery management chipset has changed several times and that has required firmware changes.

[JSWolf]

Has anyone tried an A2 microSD card in a Kobo and if so, has it made any noticeable speed difference?

[Semwize]

Originally Posted by JSWolf

Has anyone tried an A2 microSD card in a Kobo and if so, has it made any noticeable speed difference?

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)

[DNSB]

Originally Posted by JSWolf

Has anyone tried an A2 microSD card in a Kobo and if so, has it made any noticeable speed difference?

Originally Posted by Semwize

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.