Two 32Gb SD cards, different capacities after formatting

[Module 79L]

Today I did a more thorough test of all the G1W-H's alternative firmwares and for that I used an "older" 32GB SanDisk card (don't know what class it is, it doesn't say), which I haven't use in a while. I formatted it first in the camera and after that in the laptop, before transferring each following firmware.

The first time I connected it to the computer I noticed it had 31,2GB of available space, which was odd because they usually end up with less after formatting. I grabbed the card that I use in the camera, a 32GB Class 10 Kingston, connected it to the computer and it only has 29GB of available space!
I saved all the files that were there and formatted it also in the camera, just to compare, and it was the same thing.

Why does the SanDisk have more available space than the Kingston? We're talking about more than 2GB! It's a lot.

 

[SoCalDude]

If you are using Windows, when you format the card, are you using the "Quick Format" option? If so, try them both without that option so it will do a low level format.

One reason is that during a low-level format, all the sectors on the card are examined. If any are "bad", then they are marked as bad and are unusable--thus, reducing the amount of available capacity.

It's not uncommon for memory cards (and hard disk drives, for that matter) to have a small amount of bad sectors. Those devices that have over the "allowed" amount of bad sectors are sometimes sold to other companies and branded as some other "no-name" brand.

I should add that in the normal course of use, bad sectors can develop. Could this be the case with your cards? Possibly, but 2 GB seems like a lot, but you never know...

 

[Sunny]

Test both with h2testw program.

How to test SD cards?

 

[Module 79L]

If you are using Windows, when you format the card, are you using the "Quick Format" option? If so, try them both without that option so it will do a low level format.

One reason is that during a low-level format, all the sectors on the card are examined. If any are "bad", then they are marked as bad and are unusable--thus, reducing the amount of available capacity.

It's not uncommon for memory cards (and hard disk drives, for that matter) to have a small amount of bad sectors. Those devices that have over the "allowed" amount of bad sectors are sometimes sold to other companies and branded as some other "no-name" brand.

I should add that in the normal course of use, bad sectors can develop. Could this be the case with your cards? Possibly, but 2 GB seems like a lot, but you never know...

I just spent the better part of 45 minutes waiting for the Kingston's low level formatting to finish and the size is still 29GB. Mind you, the Kingston only has 3 months, so if there were any bad sectors in any of the cards they would be on the SanDisk, which is almost a year old.
Another thing I remembered: I don't know what kind of formatting the camera does but I formatted both cards in the camera and the capacity also didn't change.

I don't know if it's relevant or not but I used the SanDisk on the camera this afternoon and when I transferred the files to the HDD the average transfer rate was 10MB/s, so it's not a Class 10. The Kingston's ATR is 16MB/s.

 

[Module 79L]

This morning when I turned the camera on with the freshly low level formatted Kingston card, it displayed a warning that said something like "Wrong file size, please format the card". Apparently the low level FAT32 formatting is not suitable for the camera.
I know it's best to always format the cards on the camera, and I always do when I use them for other purposes, but the question of the different capacities remains to be answered.
There's one thing I haven't tried yet, though: to see if the SanDisk card's "extra" 2.1GB of available space translates into more recording time.

 

[jokiin]

different cards, different controller chipset used, different grade of flash, lots of influences, there's always a difference between brands in formatted capacity, quite normal in my experience

 

[Module 79L]

Ok, we all know that any type of storage device loses capacity after formatting, there's nothing new there, but what puzzles me is that the SanDisk only loses 900MB vs the Kingston's 3GB! Are the hardware differences so big that one card loses so little and the other so much? I mean, the FAT32 file system must have a fixed amount of space it takes from the total capacity of the storage device, or am I wrong and it depends on the hardware of the device?

Btw, the "extra" 2.1GB in the SanDisk translates into an extra 24min of recording capacity. Too bad it isn't a Class 10...

 

[Sunny]

All cards keep some space reserved for system and different brands may have different rules for that.

 

[SoCalDude]

I'm assuming when you formatted on the computer, you used FAT32 and not exFAT nor NTFS. What cluster size did you use?

 

[Module 79L]

I'm assuming when you formatted on the computer, you used FAT32 and not exFAT nor NTFS. What cluster size did you use?

The Windows formatting tool assumes FAT32 with a 32 kilobytes cluster size by default for these cards. When I formatted the card during the firmware tests I never changed those settings and the camera always recognized the card. When I did the low level formatting I changed the cluster size to default and the camera didn't recognize the card's file (cluster?) size, so I guess the correct cluster size is 32 kilobytes.
No matter what I do to them each card's capacity never changes, so it must be like Sunny says. It's a shame the SanDisk isn't Class 10 because those extra 24min could be very handy.

 

[SoCalDude]

Hmm...unless Windows 8 (or 8.1) changed the default cluster sizes, the default size for a 32GB volume is 16KB.

 

[Module 79L]

I'm using Windows 7 x64 SP1.

Here's the print screens of the two cards' formatting settings. Both cards were formatted in the camera:

SanDisk

Kingston

I know it's in Portuguese but I think you don't need to know the language to understand it. However, if you want me to translate anything, just let me know.

 

[SoCalDude]

Does it have a "Tamanho da unidade padrão" under "Tamanho da unidade de alocação"? If so, try that one.

Also, just to confirm, you had unchecked the "formatação rápida", certo?

 

[Module 79L]

Does it have a "Tamanho da unidade padrão" under "Tamanho da unidade de alocação"? If so, try that one.

Are you referring to the "Tamanho de atribuição predefinido"?

 

[SoCalDude]

Yes. My Spanish and Portuguese are a little rusty.

...and try unchecking the "Formatação rápida" checkbox.

 

[Module 79L]

...and try unchecking the "Formatação rápida" checkbox.

I already did that yesterday, like I wrote on post #4. This is how I formatted the card...

...but to no avail. The capacity remained at 29GB and the camera didn't recognize the card.

 

[reverend]

Windows doesn't do a low level format when it's not a quick format - low level formatting is a term from a bygone era that you can't do on most interfaces these days.

There have been reports of a few cameras here that don't like it when the block size is changed - if you format it in camera you can use something like chkdsk or msinfo32 to see what block size the camera is using.

The storage industry uses a different numbering format (powers of 1000) to that of RAM manufacturers (powers of 1024) - it's a mess and it annoyed me back in the days of 540MB HDDs and it's just got worse over the years as people ask where the missing space is! Windows uses powers of 1024 to determine storage on disks including files - so a 1MB file is 1048576 (1024x1024) bytes but the storage manufacturers class 1MB as 1000000 (1000x1000) bytes - you can see where it's quickly starting to sound stupid

Due to the way flash memory fails some manufacturers intentionally reserve some space so that bad blocks can be reallocated - that usually tends to be on the higher end cards though and some brands will just lock the entire card into read only mode instantly. It's supposed to be a good will gesture as it means your data is safe when the NAND is on it's way out but it just annoys dashcam users

From the point of view of a digital camera I prefer the method of cards failing like that though.

 

[Module 79L]

There have been reports of a few cameras here that don't like it when the block size is changed - if you format it in camera you can use something like chkdsk or msinfo32 to see what block size the camera is using.

I assume the 32 kilobytes as the card's correct block size because the formatting tool gives me a different block size for each different flash drive connected to the computer. For instance, a 8GB Kingston pen drive has this block size:

 

[reverend]

Yes they vary depending on the volume size as you can see here:

https://support.microsoft.com/en-us/kb/140365

 

[Module 79L]

If the camera formats the cards in FAT32 with a 32Kb block size, there must be a reason for it and apparently Windows formatting tool "respects" that, otherwise it would always show a 16Kb block size for FAT32, right?