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Old Apr 1, 2009, 8:26 AM   #21
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TCav wrote:
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And every manufacturer says something like "Specifications are subject to change without notice." Just because a product is advertised as 'Class 4' doesn't mean you have a valid beef if the one you buy is only 'Class 2', unless that fact was concealed by the packaging.
Exactly - therefore I wrote:

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I am writing this to warn others because if I've know before what I know now I would be much more careful.
I've trusted SanDisk before and this trust has blinded me.... what surprised me is missing more information about this on the net. This thread is the only so far being specific about Lexar cards, and I wanted to add SanDisk to the list.:evil:
Caveat emptor – double check speed ratings.
When the salesperson gave me the card to which I've already agreed as I "knew" the specs - I did not check the Class rating again - my mistake for sure.

I hope however that this practice of "Specifications are subject to change without notice." will not take ground because I would not like to go buying 20x zoom - 10 MP camera only to find out that it was announced and sold as a such before, but what I actually bough is 10x zoom - 5 MP - one ... aranoid:
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Old Apr 1, 2009, 10:18 AM   #22
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Some more research shows suspicion that Class rating degradation of Ultra II from Class 4 to Class 2 is part of a marketing gimmick to peddle 'new' Video HD Class 4 at higher price. :roll:

You can read about this at (somewhere in the middle) : http://www.dslr.nl/?cat=workshops&id=1318, if you understand Dutch, if not you can try some translation like Yahoo or Google (I've tried to insert links to translated pages, but forum text editor was messing them up).

Yahoo gives better translation of the original meaning ...


In any case picture of cards speak for themselves. :?

I have to remark on quite smaller Class 2 logo as compared to older Class 4 logo on Ultra II - if not concealing it is not making it obvious neither.

The article mentions that many shopkeepers were not aware of this 'marketing move', so I feel less ashamed of my 'ignorance'. :G






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Old Apr 1, 2009, 11:23 AM   #23
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DonalDuc wrote:
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Corrrrection: right is - SDHC class! SD cards have NO class! Didn't you know this?
From the SD Association websiteHome » Developers » SD Technology » SD Speed Class:

"These new speeds are available in a new specification defining the minimum data transfer speeds for both SD/SDHC memory cards and SD/SDHC host products. This enhancement is easily recognized by three levels of Speed Class, class 2, 4 and 6."

The Classes are for both SD and SDHC cards.
It seems that SD Association guys are confused themselves, referenced page also says that only SDHC have guarantee for the minimum speed:

"The SD Association has specified operating conditions for SDHC memory cards to guarantee the minimum speed according to the card's speed class. Class logos are provided to help identify cards that comply with these specifications"

So no guarantee for SD cards :?

While Home » Developers » SD Technologyalso confuses:

- Both SD and SDHC: "The SD Association established a new specification rating for the minimum data transfer for standard and high-capacity cards, as well as both types of host products."

- Only SDHC: "The three SDHC speed classes — Class 2, Class 4 and Class 6 — transfer data at least 2, 4 and 6 MB per second, helping you to guarantee performance of your products. "

Given that speed classes were introduced in SDA 2.0 specs,for the SD (non SDHC) card to have speed class rating it has to conform tonew specswhich would make it not compatible with the old standard spec, so it could be used only with new SD/SDHC host devices? :?

As both SDHC and speed classes were introduced together in SDA 2.0, it is easier to make them related, but technically speaking it probably not necessary.

How to explain it with marketing terms to convey compatibility is another story.

It does not seem that SDA is doing so great, I am probably too technical to always prefer simple solutions, like it was with USB: V1.1 and V2.0

On the other hand both USB 2.0 devices and hosts are backwards compatible, while with SDA 2.0, only hosts are backwards compatible ...

To conclude, I doubt anybody will make SD card (<= 2 GB) using new features of SDA 2.0 specs (I wrote too much already) ...
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Old Apr 1, 2009, 8:36 PM   #24
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The PNY webpagestates that their 2GB Optima Secure Digital™ (SD) 60X is Class 4.

The SD Card Association's Simplified Version of PHYSICAL LAYER SPEC states:

"High Capacity SD Memory Cards shall support Speed Class Specification and have performance more than or equal to Class 2."

It does not, however, say that SD Cards (as opposed to SDHC Cards) can't or don't meet the Classes. What it does say that there is a Class 0 (Zero), and "These class cards do not specify performance. It includes all the legacy cards prior to this specification, regardless of its performance."

In other words, there's nothing keeping newer 2GB and smaller SD Cards from being classified as Class 2, 4 or 6.
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Old Apr 2, 2009, 6:17 AM   #25
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TCav wrote:
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The PNY webpagestates that their 2GB Optima Secure Digital™ (SD) 60X is Class 4.

The SD Card Association's Simplified Version of PHYSICAL LAYER SPEC states:

"High Capacity SD Memory Cards shall support Speed Class Specification and have performance more than or equal to Class 2."

It does not, however, say that SD Cards (as opposed to SDHC Cards) can't or don't meet the Classes. What it does say that there is a Class 0 (Zero), and "These class cards do not specify performance. It includes all the legacy cards prior to this specification, regardless of its performance."

In other words, there's nothing keeping newer 2GB and smaller SD Cards from being classified as Class 2, 4 or 6.
Interesting, thanks for the info, especially the specs.

On the page you you already referenced it says:

"With the new Speed Classes, the host product has the option to check the fragmented state of the card and immediately calculate the write speed in each part of the card. The host can then determine where best to write the data according to its speed requirement."

So I thought that new specs changes the protocol - I wonder how old SD hosts can deal with this new option just quoted.

Perhaps it is answered in the specs you provide - I'm curious to read it ...
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Old Apr 2, 2009, 7:56 AM   #26
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TCav schrieb:
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The Classes are for both SD and SDHC cards.
Do you believe ALL what's printed? Or are this your own rules?

SDHC defines Class 2/4/6, but NOT SD 1.0/1.1

Laughing:

Sandisk Extreme III 16 GB 30 MBs ...... € 109 - € 130
Transcend 16 GB class 6 speed ~ 10-11 MBs ... € 26 - € 32

fast enough for EVERY camera!

Sandisk = money for the cat - dealers are rubbing their hands

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Old Apr 2, 2009, 12:11 PM   #27
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DonalDuc wrote:
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SDHC defines Class 2/4/6, but NOT SD 1.0/1.1
No. The SD Specifications, version 2.00, defines both SDHC and Class 2/4/6. Further, it requires that SDHC cards meet at least Class 2. However, it does not exclude SD Cards (as opposed to SDHC Cards) from the speed classes.

Perhaps you could take the time to read the spec before you reply.

Here, again, is a link to the SD Card Association's Simplified Version of PHYSICAL LAYER SPEC
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Old Apr 4, 2009, 11:02 AM   #28
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You are good in finding excuses.

SDs are thrown in "Class 0", not specified.

SDHC only are divided in class 2/4/6






[align=left]3.4 Speed Class[/align]

[align=left]
Four Speed Classes are defined and indicate minimum performance of the cards
[/align]



[align=left]
Class 0 - These class cards do not specify performance. [/align]

[align=left]It includes all the legacy cards prior to this specification, regardless of its performance[/align]


[align=left]Class 2 - Are more than or equal to 2 MB/sec performance.
[/align]


[align=left]Class 4 - Are more than or equal to 4 MB/sec performance.
[/align]


[align=left]
Class 6 - Are more than or equal to 6 MB/sec performance.
[/align]


[align=left]High Capacity SD Memory Cards shall support Speed Class Specification and have performance more than or equal to Class 2.[/align]
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Old Apr 4, 2009, 12:19 PM   #29
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BUT THERE'S NOTHING IN THE SPEC THAT SAYS THAT SD CARDS CAN'T BE CLASS2 , 4 OR 6.

AN SD CARD CAN MEET THE NEW SPEC WITHOUT BEING AN SDHC CARD.

GET IT?
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Old Apr 4, 2009, 4:30 PM   #30
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Show me ONE ... ONLY ONE! .... SD card with Class2 or Class4 or Class6 ...

then you get Nobel Award!



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