4GB SD slow write speed

[KenSong]

All those who are using 4GB cards with their LD, did you notice write speed is slower than smaller cards? I get fast read and access but slower writes using an Apacer 150x 4GB card. Anyone has 4GB cards that has fast write speed?

[KenSong]

I have added my VFS Mark Result just for reference. File seek and read is nice but look at the really sloooow write speed! Anyone care to post their result?


File Create: 48%
File Delete: 21%
File Write: 12%
File Read: 504%
File Seek: 1311%
DB Export: 16%
DB Import: 91%
Record Access: 1005%
Resource Access: 914%

VFSMark: 435

[dmitrygr]

fat32 driver uses fat32 fs when 2gb or more, this is characterized by less file overhead and much slower file writes.

[KenSong]

Does this mean it applies to all 4GB Flash? Why is my 4GB Compact Flash replace of the Microdrive much faster?

[dmitrygr]

because microdrive is slower physically then the card

[KenSong]

Sorry dmitrygr, let me rephrase. Why does the 4GB Compact Flash writes much faster than the 4GB SD? Both uses the same fat32 driver right? I know CF is faster than SD but not that much faster.

[Pathdoc]

Here are the results with VFSMark on my 4GB Transcend 150x with my LD.

File Create: 504%
File Delete: 201%
File Write: 321%
File Read: 627%
File Seek: 983%
DB Export: 392%
DB Import: 83%
Record Access: 365%
Resource Access: 325%

VFSMark: 422

[SEANxk]

Here are the results with VFSMark on my 4GB Transcend 150x with my LD.

File Create: 504%
File Delete: 201%
File Write: 321%
File Read: 627%
File Seek: 983%
DB Export: 392%
DB Import: 83%
Record Access: 365%
Resource Access: 325%

VFSMark: 422

Your result is SD or CF?
tkz

[Pathdoc]

I am using an SD card.

[mrp123]

All those who are using 4GB cards with their LD, did you notice write speed is slower than smaller cards?Yes. I have not found any way to dramatically increase the actual file write benchmark. It seems to be a limitation of how the card is made from mfr. to mfr.

I also commented on this before in another thread here (http://www.1src.com/forums/showpost.php?p=947387&postcount=17). My SD card is Transcend 150x 4 gig and my CF is SanDisk Ultra II 4 Gig.

In addition to my previous post, I'll mention I also noticed that my Rosewill 512 MB formatted in FAT32 slowed the card terribly for all cluster sizes. The 512 MB card performed very, very well in comparison when formatted FAT16. Again, the larger the cluster size, the better the benchmarks. Try it yourself.

[dmitrygr]

Sorry dmitrygr, let me rephrase. Why does the 4GB Compact Flash writes much faster than the 4GB SD? Both uses the same fat32 driver right? I know CF is faster than SD but not that much faster.





um......SD: 1 bit interface w/ a 12 MHz max clock
cf: 16(?) bit interface w/ a 32 mb clock

[KenSong]

Understood...oops...sorry for being so ignorant. Thanks dmitrygr.

[KenSong]

Here are the results with VFSMark on my 4GB Transcend 150x with my LD.

File Create: 504%
File Delete: 201%
File Write: 321%
File Read: 627%
File Seek: 983%
DB Export: 392%
DB Import: 83%
Record Access: 365%
Resource Access: 325%

VFSMark: 422

Pathdoc,

Those are good results. Did you format the card first on the LD before using? And is your test made before or after you filled up your card? How much data do you have on it?

Strange that mrp123 has the same card and he is facing the same issues I have with write speed.

[Pathdoc]

Formatted the card in the LD before use. Testing was done with 1475.2 MB free out of 3950.2 MB (per CardInfo).

[+Kardboard+]

format E: /FS:FAT32 /A:32K

Replace "E:" with your SD card's drive letter. 32k chunks = faster 4Gb card, but at the cost of some wasted space.

[KenSong]

errr...can you please explain that in layman's language? Sounds like an excellent solution and I don't mind some space wasted. How...?

[+Kardboard+]

Assuming you're using Windows, go to the Start Menu, click Run, then type in "command". You'll see an old DOS prompt, and that's where you type this in:

format E: /FS:FAT32 /A:32K

Replace "E:" with your SD card's drive letter. This will reformat your card (wipe it!) in the FAT32 file system (required for 4Gb cards) and in 32k clusters. Usually it's formatted in something like 8k clusters so you don't waste as much space, but it's a heckuva lot slower.

[KenSong]

Thanks. I am actually on a Mac but have access to a PC so I'll do that and report back results.

[+Kardboard+]

Good luck!

[KenSong]

Okay, I have done the reformating to FAT32 and the surprise result is a slower VFS Mark! I have the results below.

Format in LD / PC with FAT32
File Create: 48% / 110%
File Delete: 21% / 86%
File Write: 12% / 16%
File Read: 504% / 464%
File Seek: 1311% / 983%
DB Export: 16% / 75%
DB Import: 91% / 82%
Record Access: 1005% / 786%
Resource Access: 914% / 752%

VFSMark: 435 / 372

Any idea why the Write speed is only slightly faster? Hope there is some explaination as both test were done with the same amount of data stored. Thanks.