Clara Clara or Glo, replacing the internal SD card, which is best

[ZodWallop]

I've read repeatedly about replacing the internal card on a Glo or Clara. I'm thinking of trying it. I do remember reading that most class 10 cards are optimized for large block storage, but small block storage is more important in an ereader.

What specific 32/64GB card would you recommend? Amazon US links are appreciated. (I am well aware that I shouldn't buy from Marketplace sellers for SD cards).

My Clara is quite a bit speedier than my Aura. I'm not worried about a speed boost. I just don't want to inadvertently cause it to run slower.

I was looking at this card: SanDisk Ultra 64GB microSDXC UHS-I card with Adapter - 100MB/s U1 A1 - SDSQUAR-064G-GN6MA

[ReaLx3m]

Not sure about the Sandisk A1 version you posted but i assume its worse than Samsung evo plus.
As i compared the 128GB Sandisk Extreme with A2 specification which should have had more than double the 4k performance than the Samsung Evo Plus 32GB, but it turned to be about the same, in reality bit worse. Not sure if its a card reader limitation. Tested on 2 different usb 3.0 readers, but dont have the sandisk extreme reader(which should be one of the fastest available) to do a test to get a definite picture.
Boot time performance on the h20 was around 30 seconds with Samsung evo plus 32GB, and around 40 with Sandisk Extreme A2 128GB.

[frostschutz]

anything is fine really. it's an ebook reader not a rocket launcher. there is only so much you can do with the sd card.

kobo bootup is slow because the init script is slow, but it doesn't matter since once booted you keep it in standby forever, right?

[ReaLx3m]

Originally Posted by frostschutz

anything is fine really. it's an ebook reader not a rocket launcher. there is only so much you can do with the sd card.

kobo bootup is slow because the init script is slow, but it doesn't matter since once booted you keep it in standby forever, right?

I do also notice an improvement in cover loading over the factory sd that came with the H20.
So while one could live even without that bit of boost as most of the time is spent inside a book, why not have it. No harm only gain, more time to spend inside a book . The sd could find a home in a more taxing device later in its life, you never know.
And with pretty insignificant difference in prices nowaday for sizes mentioned, i see no reason not to get the best available.

[ZodWallop]

Originally Posted by frostschutz

anything is fine really. it's an ebook reader not a rocket launcher. there is only so much you can do with the sd card.

kobo bootup is slow because the init script is slow, but it doesn't matter since once booted you keep it in standby forever, right?

I understand that. As I mentioned, I'm not so concerned about boosting the speed. I just didn't want to get a card that would be slower than what's in the Clara already.

I'm looking at these two. Not sure what the difference is, though I'll likely buy the second, slightly more expensive one:

Samsung 64GB MicroSDXC EVO Plus Memory Card w/ Adapter (MB-MC64GA)

Samsung Evo Plus 64GB MicroSD XC Class 10 UHS-1 Mobile Memory Card for Samsung Galaxy S7 & S7 Edge with USB 2.0 MemoryMarket Dual Slot MicroSD & SD Memory Card Reader

[abij]

Originally Posted by ZodWallop

I understand that. As I mentioned, I'm not so concerned about boosting the speed. I just didn't want to get a card that would be slower than what's in the Clara already.

I'm looking at these two. Not sure what the difference is, though I'll likely buy the second, slightly more expensive one:

Samsung 64GB MicroSDXC EVO Plus Memory Card w/ Adapter (MB-MC64GA)

Samsung Evo Plus 64GB MicroSD XC Class 10 UHS-1 Mobile Memory Card for Samsung Galaxy S7 & S7 Edge with USB 2.0 MemoryMarket Dual Slot MicroSD & SD Memory Card Reader

I just noticed the two ereaders you mentioned have the same CPU as my Aura HD. The processor is i.MX507 whose documentation says (p. 13)

Up to 200 Mbps data transfer for SD/SDIO cards using four parallel data lines

So any transfer speed higher than the theoretical upper bound 25MB/s will most likely be capped at that point.

[frostschutz]

Originally Posted by abij

So any transfer speed higher than the theoretical upper bound 25MB/s will most likely be capped at that point.

16-18MiB linear read speed

~1600 IOPS according to fio randread test

with a 32GB SanDisk Ultra card on my H2O

yeah, I don't have an extreme card to see if IOPS could go higher

that MIGHT make a difference but again it's not a rocket launcher... and at some point the performance issues will be elsewhere ( switching over to koreader might be mandatory as the nickel sqlite database will kill you if you actually fill it up ... )

[Semwize]

Originally Posted by ZodWallop

I'm looking at these two. Not sure what the difference is, though I'll likely buy the second, slightly more expensive one

These are identical SD cards. The difference in the attached adapter (card reader).

[mathil]

I substituted the internal SD card of my Glo HD with a 16GB Sandisk Ultra (class 10) that I had lying around the house. I'm not an expert by any means, but the reader is definitely faster than it used to be (though it is true that it's not the kind of difference you'd notice while reading). I mostly notice it while processing new books into the database and in navigating the library (I have 3000+ kepubs on it and 50 pages of collections, so any small improvement is welcome).

[ReaLx3m]

Originally Posted by ZodWallop

I understand that. As I mentioned, I'm not so concerned about boosting the speed. I just didn't want to get a card that would be slower than what's in the Clara already.

I'm looking at these two. Not sure what the difference is, though I'll likely buy the second, slightly more expensive one:

Samsung 64GB MicroSDXC EVO Plus Memory Card w/ Adapter (MB-MC64GA)

Samsung Evo Plus 64GB MicroSD XC Class 10 UHS-1 Mobile Memory Card for Samsung Galaxy S7 & S7 Edge with USB 2.0 MemoryMarket Dual Slot MicroSD & SD Memory Card Reader

The second one is more expensive because it comes with a card reader(and advertised for samsung galaxy ), which imo would be wasted money as it is usb 2.0. If you need one, you can get an usb 3.0 reader for 2-4$ on aliexpress, probably on amazon too.
Heres an example . Its an ok brand too, not the absolute bottom of the bin as is usually the case with cheap chinese electronics. Have had few gadgets from them.

[BloodRagg]

Whats a good card ? Difficult to say as the speed/IOPS depend on the combination of you e-reader and the sd card itself. Cards performing well in a PC, camera or raspberry pi do not have to perform well in the e-reader. As you can see here: https://www.mobileread.com/forums/sh...d.php?t=315976

If you want performance, you pay or you take a gamble with multiple cards.

[ZodWallop]

Originally Posted by Semwize

These are identical SD cards. The difference in the attached adapter (card reader).

Originally Posted by ReaLx3m

The second one is more expensive because it comes with a card reader(and advertised for samsung galaxy )...

I figured they were the same, except the second one (this one) is listed as class 10 and has a 1 on it (UHS 1?).

The other card (this one) doesn't mention what class it is and has a 3 on it.

[Semwize]

ZodWallop,
U3 faster

But I am confused that there are no such cards (SD EVO PLUS 64 U3) on the official Samsung website))

It is necessary to clarify, and fakes can be on the Amazon.

[ReaLx3m]

Originally Posted by ZodWallop

I figured they were the same, except the second one (this one) is listed as class 10 and has a 1 on it (UHS 1?).

The other card (this one) doesn't mention what class it is and has a 3 on it.

Different sellers can use different terms for marketing same item to make it seem better. In reality there is only one Samsung Evo Plus model with red color, only difference is the size. There are orange ones(older model), but those are Samsung Evo(without the plus).

U3 is a specification for the cards speed, and it means that you get minimum of 30MB/s sequential write speed(large blocks).

Edit:
I was just looking through my purchases and there might have been sort of an update on samsung side.As i see i had purchased some u1 64gb Evo Plus cards, but im 100% sure that even the ones marked with U1(which would mean at least 10MB/s or class 10 in other words) were performing way better than that.I have two u1 32gb on me atm, and those do around 32MB/s writes.
So they might have just changed the markings to reflect the speeds theyre getting, but if you dont want to risk it, look for a 64GB one which is marked as U3 either in description or on the pics.

Edit2:
Got interested on the subject , turns out there was an update in march 2017.They used to be "Samsung Evo+" , and after the update renamed to "Samsung Evo Plus" .
As it is very unlikely that there are still new ones from the old model left in circulation, i would avoid sellers that advertize the older model as it could be fakes that cant perform to the updated ones level and hiding behind the older model spec. Or best case scenario the seller doesnt know what hes selling as is often times the case with chinese sellers(as far as i know there are lot now on amazon too), or hasnt updated the listing for ages and in the end you get the new one with U3 spec.

If youre uncertain where to get a genuine one, this is a tried and tested hong kong vendor that i have used for lot of purchases. They offer warranty for 6 months on every item, and if its within the first 3 months they even pay you back for shipping the item to them.
Have had a case with doa items, and they did honor that warranty(got shipping back cost reimbursed). Not sure how amazon deals with stuff like this as it is not available in my country.
Items usually take 1-2 weeks to get to me with Hong Kong registered airmail if item is marked as "ships next day" or "in stock". Your mileage may vary.

Since youre in usa, this also might be a good option. Its a reputable long time store, not sure how much they charge for shipping though.

[BloodRagg]

U3 says nothing about the cards application performance which is what you need.Its nice to copy books with good speed, but how often is this relevant ?

Newer cards come with A1 and A2 labels, this is an indication for application performance.
IIRC A1 is 500/1500 IOPS and A2 2000/4000 IOPS. This is what makes your e-Reader fly.
OS's and Applictions have small random read/writes 4k/8k/16k, the faster they are read/written the more performance you experience.

You can have all the speed in the world but you only notice performance if the current configuration is under-performing. If the software requires 600 IOPS but the card maxes out at 300, you will notice that performance pretty quick. That also means that anything over 600 is wasted money. Keep in mind though that if the software changes, like the update from 3.x to 4.x, the IOPS requirement may also change.
So Id rather overpay a bit to be on the safe side.

So how about benchmarking the cards in the Kobo e-reader and posting the results ?
(benchmarking in other devices doesnt mean anything, if found that out the hard way)

https://liliputing.com/2018/10/sandi...k-2k-iops.html