# class 6 20MB/s vs class 10 22MB/s SDHC cards



## pezj (Sep 26, 2010)

i recently bought a pansonic gold class 10 SDHC card, its max transfer  rate is 22MB/s, i already have a core micro class 6 SDHC card with a max  transfer rate of 20MB/s, my question is, will the extra 2mb make a big  difference? ideally i want longer video, and more shots per burst, i  have a nikon D5000 if that helps.


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## Whootsinator (Sep 26, 2010)

That 'more shots per burst' thing is called your processing buffer/shooting buffer/buffer zone/buffer thing, and is dictated by your camera, not the card. The card speed can affect how quickly new images are written to it, but not how many can be queued for processing/saving.

I hope that helps.


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## pezj (Sep 26, 2010)

thank you that does help, although i'm still confused about the extra 2MB/s the class 10 gives, will it have any significant effect on my shooting and all that? what are the benefits of getting a class 10 rather than class 6? i already have a class 6 so i'm not sure if i really need the class 10


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## Whootsinator (Sep 26, 2010)

Let's say a photo is 6MB in size... 6/20=.3, meaning it would take .3 seconds to save that file. 6/2=~.27, so ~.27 seconds to save that image. If you're a sports photographer and and take massive high-fps strings of shots, it might prove to be useful. .27*15=4.05 seconds to save all of those images. .3*15=4.5 seconds to save those files. It saves a little under half a second if you take a string of 15 photos, of say a defender closing on on a ball carrier for a tackle. In a high-speed game where your shots count for more than just your photostream, it's probably worth it. If that's the case you probably don't even have to worry about it though because you already have the best, and you probably didn't pay for it.

In short, no, that speed difference does not make a practical difference to 99.8% of photographers while shooting. It is a 10% increase in speed of something that is already very fast.

It would however make a larger difference when transferring those files from your card to your computer. 

(500 images * 6MB each)/20MB/s = 150s to transfer all 500 images. 

(500 images * 6MB each)/22MB/s = ~136.36s to transfer all 500 images. 

Is it worth saving 20 seconds? Not really....

Would it be worth it for a hobbyist videographer shooting HD video? Possibly.



All of this pertains to the SPEED ONLY. I have no idea what other differences there may be between a Class 6 and Class 10.


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## pezj (Sep 26, 2010)

thank you, you are very helpful, i was doing some research, and in the  manual it states while using the sandisk extreme 3 (30MB/s) {renamed to  class 10} it has a buffer capacity of 11 shots on RAW, with a normal  class 6 card (20MB/s) {i have a core micro card} it can take 9 RAW  shots, and with "long exposure noise reduction" turned on the number  falls to 6 RAW shots

so i may be wrong but it seems under ideal conditions, the 10MB/s  difference amounts to 2 extra pictures before the camera needs to buffer

so i guess to answer my own question as far as the difference between  the 20MB/s class 6 and the 22MB/s class 10, you can add half a RAW image  onto the buffer

if my calculations or the whole theory is wrong please let me know 

_however i did find a big difference between the cards as far as JPEG is concerned_

in case anyone is interested in other formats such as just JPEG (fine,  normal, basic) + (large, medium, small) i compared what my class 6  (20MB/s) can do under ideal conditions vs. the 30MB/s sandisk (specs found in nikon D5000 manual pg. 215) 

(all the JPEG+RAW, large, medium, small are the same for both cards, 7 shots within the buffer)

*JPEG fine* 
*large* - 13 vs. 63, *medium* - 19 vs. 100, *small* - 33 vs. 100

*JPEG normal* 
*large* - 21 vs. 100, *medium* - 33 vs. 100, *small* - 61 vs. 100  

*JPEG basic* 
*large* - 33 vs. 100, *medium* - 61 vs. 100, *small* - 99 vs. 100


as a side note regarding video, the information i gathered from photo  stores, is that the better the MB/s the less choppy the video will be,  however having a class 6 myself i can safely say that at 20MB/s the  video looks perfectly fine and smooth, but i'm sure in some way or  another the video might be smoother at 22MB/s and 30MB/s but i'm not  convinced it will be anything drastic or noticeable  

i personally know how hard it is to find the information you need so i hope as far as class 6 vs. class 10 all this helps


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