SDcard speed


Jan 6, 2003
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#1
I have a slow writing Sigma DP1, so the difference in write speeds to different cards wasn't really noticeable.

Recently I got a new 16gig Sandisk Ultra label as up to 30mb/s.
In the camera, the write speed is pretty similar to a old class4 Transcend 32gb card (15mb/s).

The surprising thing is that file copy from a card reader shows that the class4 transcend is faster, up to 15-16mb/s writes, for large 1gb+ video files, and around 7.5mb/s for the smaller photo raw files. The Sandisk Ultra barely breaks 7.5mb/s for large 1gb+ video files,and 6.5mb/s for raw photo writes.

The write speed is reported from win7 copying the same set of files from the notebook back on to the SD cards using the same card reader/writer.

Can anyone please report your 16gb Sandisk Ultra sdcard write speeds. Thanks.
 

Last edited:

s1221ljc

Senior Member
May 7, 2006
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#2
Google sosfakeflash & download the h2testw program to test the read/write speed of your SDHC Ultra cards using a card reader. You may be shocked that the write speed of the card is way way below 30mbs thats assumed for this card. Of course, it is only represented as "up to 30mbs transfer speed, write speed lower" in the fine prints so the actual 6.6mbs is "not" misrepresentation, even if it is lower than those cards with 15mbs indicated! Read speed is about 18mbs, slightly better than the 15mbs of the older cards but still far from the 30mbs. Playback of HD videos looks slightly faster/smoother/better to my eyes in this case. I think someone ought to raise this dishonesty concerning the write, & read speed of these cards to the manufacture/distributer or the authorities/consumer groups....

You can also roughly gauge the write speed visually by copying large video files from your PC to the cards & the time stated on the progress bar will give you an indication of its speed in comparison.
 

Last edited:
Jan 6, 2003
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#3
I wonder if the card manufacturers publish the kind of hardware parts need to recreate the claimed card speed rating.
 

Rashkae

Senior Member
Nov 28, 2005
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#5
so which brand is best for video cam?
Just stick to a reliable brand like Sandisk, Kingston, Lexar, etc. "which is best for video cam" is soooooo generic a question it's actually hard to answer without writing an essay.
 

Wizongod

New Member
Nov 25, 2011
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#6
I've have had terrible experience with the Sandisk Ultra 20MB/s class 6. They write slower than my toshiba class4.
 

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