Quote:
Originally Posted by ahuskins
About the block size...A larger block size will limit your actual storage capacity on the card but can increase performance. If you set it to 32kB blocks then every file, say a 1kB file will take up 32kB. Waste of space IMHO. The recommended starting size for a FAT32 disk is 4kB. The maximum is 32kB. I would guess that unless you are installing a very disk intensive program to your card; or are constantly transferring large files back and forth to the card a smaller block size would be better.
Just my 2C
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That's what I though initially too and I used to reformat my cards and choose the default 4k block size. After one of these reformats I found the performance of the card dropped way down. I mean when deleting files it felt like I was deleting off of *floppy* instead of SD. I thought I had broken the card somehow. Then I examined an out of the box card and found it came from the factory with 32k block size. I reformatted the card back to the factory 32k block size and performance was back to normal.
For my usage, the SD card is 90% filled with large MB files like pictures, movies, install files, rom images, and GPS maps so the 32k block size waste is very minor. If there is no performance difference for your card then choose 4k, but after my experience, I always test my cards before changing the block size. For some cards, 4k is much slower than 32k. For other cards 4k and 32k perform the same. I've never found 32k to perform worse than 4k, so I just routinely use 32k now.
If it was just performance difference of a few percent I would agree with you, but in the cases where it matters, the difference is much greater. The transfer rate doesn't tell the whole story though, because the latency for file deletion and writing can go way up (again in the cases where the block size matters) to the point of being unbearably slow.
To get an idea how much of a difference it *could* make see this post. I say "could" because it depends on the micro controller on the card what size it is optimized for if any. I included a second post for someone on amazon who talks about the file deletion issue.
http://discussion.treocentral.com/tr...ml#post1184334
Quote:
Originally Posted by bayareastank
I've been testing backup times with Fly-Backup to the 8GB SD card formatted with different block sizes 4k, 16k and 32k vs my 2GB card.
The backup in each case is 9.3 Megs in size which compess down to about 6mb when done via fly's compression.
SO here are the numbers
2GB Corsair 133x SD card
Backup Time: 35 seconds
Data Rate: 268.1 kbps
8GB Transcend SDHC card formatted with 4k blocks
Backup Time: 7m55s
Data Rate: 22.5kbps
8GB Transcend SDHC card formatted with 16k blocks
Backup Time: 3m45s
Data Rate: 42.2 kbps
8GB Transcend SDHC card formatted with 32k blocks
Backup Time: 2m46s
Data Rate: 56.9 kbps
So the larger block size seems to yield the fastest speeds. I was running it with an 8k block size which I didn't speed test but it's between the 4k and 16k somewhere. Everything seemed to work fine except i can't write video captures direct to the SD card, even with a 4k block size i still couldn't.
I'm going to test with the 32k size and see how the apps respond. Of course using 32k size wastes more space on the drive. If your files are only say 2k in size, they still occupy 32k worth of space. So that kind of bites. But if you're keeping big stuff on the card like ROMs, movies, music, backups, the 32k size isn't that big of a deal as long as the apps all work properly.
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http://www.amazon.com/review/R3RY580...cm_cr_rdp_perm
Quote:
20 of 23 people found the following review helpful:
HUGE but s l o w..., January 28, 2007
By Rene Ritchie "author, Legends of Wingchun"
Note: Though this is definitely the card I ordered, the one that arrived wasn't labeled as 'transcend' but as 'topram'. Not sure if that makes a difference or not.
I bought this card to go with my new Treo 680. (Note, the other review is incorrect as, although the capacity will not read correctly (it maxes out at 4GB), the card will still work fine with newer Palm Treo products, and can be patched to work with others -- do a websearch for more). I like me some media, and had already filled a 2GB card with music, movie, and TV shows, and really wanted something bigger.
This card fit the bill perfectly. I've got about 5GB on it already, and it plays all the music and video files very well via pTunes and TCMP.
The only downside is that the card is *very* slow to write to, and incredibly slow to delete from. The card reader which came with it approaches bearable, but trying to delete from within the Treo itself is so slow I avoid it whenever possible.
Still, 8GB at this price is incredible.
UPDATE: I reformatted the card via command-line to use 32k block size, and this seems to have improved speed for large-sized files (music, videos, etc.)
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