SDHC Cards: Class 4 or Class 6/ 8 or 16gb

Is there any benefit to getting a Class 6 SDHC card over a Class 4 SDHC card? Is the extra speed noticable or prefered or accesable?

As for size, I see the 8gb is generally accepted as the largest size to be used (from the Acer website), but on here alot of people have used 16gb cards as expansion drives.

I'll be getting a UK spec Linux flavour machine tomorrow, so want to order an sd card and just want to check which one to go for.

Many thanks

Trencherman

 

tough to say without providing any brands. Not all class 4 cards are created equal. The Sandisk Ultra II, which are class 4, are 15MB/sec but they reserve their class 6 rating for their Extreme III line which is more expensive (marketing ploy). I have a class 4 Kingston 4GB that is fairly fast (15mb/sec read, 11mb/sec write on larger files). I will be picking up a class 6 Kingston 4GB soon to test with and see if there are any differences.

 

I haven't yet heard a definitive answer regarding the "lack of " SDHC support on at A1 flash readers. The speeds do not seem to be much slower than my "SDHC" compatible readers.

Class 6 is faster than Class 4. In my view : get the more expensive card and sleep easier knowing you got the best you could. Its not so much money to worry over. Even if its not faster on the A1, it may be faster on other machines, or on your camera, etc, where ever you choose to use it.

(Sandisk: the Extreme is only significantly faster than the Ultra if you use their own card readers)

 

Class 6 cards are not guaranteed to be faster, the class rating is only for minimum sustained speeds. I can tell you that the Sandisk Ultra II cards (15mb/sec read and write sustained) are faster than some class 6 cards, yet they are labelled as class 4. Class ratings do not indicate maximum speeds, which can differ (obviously).

 

wtf....why have a "class" rating if it does not mean 6 is better than 4? Sounds like a marketing ploy to me

 

The class rating guarantees a "minimum" sustained speed. Maximum can be anything past that. Some manufacturer's may produce some class 4 that are faster than other class 6 cards and not label them as class 6. None of them are lying, so long as they meet the minimum requirement for rating their cards under the specific classes.

 

Class 4 is 4 MB/s write.
Class 6 is 6 MB/s write.

If the write time is more than 6 MB/s there is no reason not to designate the card as class 6.

Read times are not specified. Class 4 is usually around 10 MB/s, class 6 around 20 MB/s, but it does vary from manufacturer to manufactuer. The Sandisk Ultra II would appear to be a bit better than other class 4 cards, but the write speeds are most likely still less than 6MB/s. Come to think of it I do have a Sandisk Ultra II, albeit an older 1GB SD card. It is royally spanked by my Panasonic class 6 SDHC 1GB.

 

thanks all for the info - I've ordered a class 6 sdhc from play.com because the price wasnt much different (and I'm typing this on my shiny new AAO from the sofa. Yay!!)

 

I bought a class 6 32gb sdhc card from play.com for £60 w0000tt bargin!! even get free delivery

here's the link enjoyy
http://www.play.com/Electronics/Electro ... emory+Card

 

You mean you 1GB Panasonic SD, it's not SDHC even if it has a class rating to it.

It depends on the reader/writer as well.

I agree with you but Sandisk is doing the class rating on the ultra/extreme line for marketing purposes. There is nothing that states that if the card does write faster than 4MB/sec that it must be labelled a class 6 card. That's why sandisk reserves class 6 for their upper-end memory and class 4 for the more affordable.

Write speeds on the older Sandisk Ultra II's that I tested (9mb/sec writes according to Sandisk) were what they said, I was around 9mb/sec sustained, no higher than 10.5mb/sec.