Class 10 vs UHS-1

Started Jun 15, 2012 | Discussions
Jim Holloman
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Class 10 vs UHS-1
Jun 15, 2012

The following is an exchange with SanDisk regarding UHS SD cards. Reach your own conclusion.

I purchased this SanDisk UHS-1 SC Card for use in the OM-D:
http://www.amazon.com/gp/product/B007B5RIN4/ref=oh_details_o01_s00_i00

I have received the card, and there no mention of "UHS" on the label nor on the package. Nor, does it have a 'U' letter with a '1' inside of it as you find on Transcend SD cards (number contained within a U-shape). It does have a simple 'I' on the label, but by itself such a mark has no significance.

So, I sent a message to Sanddisk. This is part of the reply:

"Please be informed that UHS-1 (Ultra high speed) is equivalent to class 10. All UHS-1 memory cards have 10MB/s of minimum data transfer speed same as a class 10 card. There is no difference in the data transfer speeds of these memory cards and also they are identical in their technical specifications as well. All SDHC and SDXC class 10 memory cards that we are manufacturing are UHS-1 also."

The last statement may be valid. I question the other assertions.

This is from:
http://en.wikipedia.org/wiki/Secure_Digital#UHS_Speed_Class with emphasis added.

"UHS Speed Class

Cards that comply with UHS show UHS-I or UHS-II ==> on the label

Also:

"UHS-II cards, to be defined in Version 4.0, further raise the data transfer rate to a theoretical maximum of 312 MB/s"

This is from: http://transcend-info.com/Press/DrT.asp?LangNo=0&axn=Detail&PrsNo=115&NewsKeyWd=&Func1No=3&Func2No=211

"...UHS-I is the fastest category of card available today with a bus interface speed of up to 104 MB/s, while UHS-II is expected to reach 300 MB/s..."

This is from:
http://sdcard-speed-guide.articles.r-tt.com/

"Beyond Class 10 is the UHS Speed Class. UHS stands for ultra high speed and includes cards that have speeds up to 312 Mb/s. The UHS speed class logo includes a number contained within a U-shape. Currently, there is only one UHS speed class: UHS Speed Class 1, which is designed for the UHS bus interface. Cards in this class will usually be noted as SDHC UHS-I or SDXC UHS-I."

This is from: http://news.thomasnet.com/fullstory/Class-10-UHS-I-Memory-Cards-aid-full-HD-video-capture-607479

"The new Class 10 SDHC UHS-I cards boast a staggering four times faster transfer rate compared to Class 10 alone, realizing transfer speeds of up to 85MB/s when paired with advanced UHS-I compatible devices."

-- hide signature --

UHS-II cards will clearly not be the same as Class 10 cards. So, to avoid such confusion, please consider labeling all of your UHS cards as either UHS-1 or UHS-II cards.

The Sandisk SD card that I purchased is a Class 10. It shows a maximum transfer of 30 MB/s (for reading only, write speed slower) -- not 85MB/s.

Thus, the information you give me is inconsistent with the information I find on various sources on the Internet.

This information is to be posted at:
http://forums.dpreview.com/forums/forum.asp?forum=1041

In a message titled "Class 10 vs UHS". Please feel free to respond to the message.

Jim Holloman
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Re: 'I' vs 'U' with a '1' in it
In reply to Jim Holloman, Jun 15, 2012

Okay, this is also at:

http://transcend-info.com/Press/DrT.asp?LangNo=0&axn=Detail&PrsNo=115&NewsKeyWd=&Func1No=3&Func2No=211

"The SD Association has announced two new high-speed performance symbols for the fastest SDXC and SDHC devices and memory cards:

The UHS-I symbol (a bold capital letter I): for products with bus interface speeds up to 104 MB/s.

The UHS Speed Class 1 symbol (a number 1 nestled inside a letter U): meaning it supports transfers of at least 10MB/s."

So the bold "I' by itself apparently represents a bus speed of at least 10MB/s, while the UHS Symbo with a '1' in it representsl a bus interface up to 104MB/s (which could also be 10MB/s or even 5MB/s since 5 MB/s it is "up to" 104MB/s. WHAT A MESS! It is a good thing that the engineers that develop the specs. are not attorneys. The judge, and jury, would never know the truth in regard to actual bus speed.

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Jim Holloman
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Re: Speeds are reversed in the last para. of prev. msg.
In reply to Jim Holloman, Jun 15, 2012

I have the speeds reversed in the last paragraph of the previous message. Time to take a break!

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newsposter
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Re: Class 10 vs UHS-1
In reply to Jim Holloman, Jun 15, 2012

I note this morning that the price difference between a Sandisk class 10 16Gb card and a Sandisk UHS-1 16gb card is about $7-

If I didn't have a half dozen 16 Gb cards, three of which are class 10, I'd go out and buy a UHS-1 card to test.

The times I'm likely to push my E-M5 past buffer-full are few and far between, probably three or four times a year. Those would be paid jobs though so investing in the proper tool is always a good thing.

But for lesser-demanding jobs, I think I have all the cards I need.

A 16gb card will hold 500+ raw images.

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Moonlight Knight
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Re: Class 10 vs UHS-1
In reply to Jim Holloman, Jun 15, 2012

Jim Holloman wrote:

"Please be informed that UHS-1 (Ultra high speed) is equivalent to class 10.

This statement contradicts Sandisk's own products. There is a class 6 UHS-I Sandisk.

http://moonlightknighthk.wordpress.com/2012/05/04/om-d-e-m5-sd-benchmark-test/

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Jim Holloman
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Re: Class 10 vs UHS-1
In reply to newsposter, Jun 15, 2012

newsposter wrote:

I note this morning that the price difference between a Sandisk class 10 16Gb card and a Sandisk UHS-1 16gb card is about $7- ...

According to the information from SanDisk sent me, there is no difference between a SanDisk Class 10 card and a SanDisk UHS-1 card. How did YOU distinguish between the two? Is one SOLD as a UHS-1 card and the other is NOT SOLD as a UHS-1 card? That seems to be the case with Amazon.

According to SanDisk, SanDisk is the "#1 Global Leader" in Flash Memory Cards. Therefore, I was astonished to read that a representative of SanDisk was claiming that SanDisk Class 10 cards are "equivalent" to SandDisk UHS-1 cards. And, in this context, what does "equivalent" mean?

I have been a "true believer" in SanDisk in the past, but the labeling (I never know if "Ultra" is better than "Extreme" or vice versa -- or if "Ultra II" is better than "Ultra I" or vice versa, etc.) has me ready to try a different brand. I now have the the UHS-1 vs Class 10 confusion. When I pay extra money for a superior product, I want to be able to understand exactly what it is that makes it a superior product.

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newsposter
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Re: Class 10 vs UHS-1
In reply to Jim Holloman, Jun 15, 2012

The difference?

Sandisks own labelling, both on the cards and the package.

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BillHinge
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Re: Class 10 vs UHS-1
In reply to Jim Holloman, Jun 15, 2012
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007peter
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Sandisk is at least HONEST, the TRUTH about MARKETING
In reply to Jim Holloman, Jun 15, 2012

Jim, you need to stop believing the lies marketers tell you and reading "Real World benchmark" instead of outrageous marketing department propaganda. San Disk is well know for its lie about their Extreme SD can push 30mb/s - when independent test reveal a mediocre 22.1mb/s One of Sandisk Representative admitted in a forum that Extreme SD was test under a specialized lab card reader that isn't available in the retail channel. Furthermore, its only test under sequential read/write rather than random read/write as most camera would do. It helps to read disclaimer and take it apart:

Sandisk disclaimer:

  • Up to 30MB/sec read speed; write speed lower. Based on internal testing

  • Up = theoretical marketing claim, under 100% ideal condition, it may reach it for a brief second

  • internal testing = special lab equipment, you're never get this speed

Analysized the Reply ( put on your Lawyer's Hat )

"Please be informed that UHS-1 (Ultra high speed) is equivalent to class 10. All UHS-1 memory cards have 10MB/s of minimum data transfer speed same as a class 10 card. There is no difference in the data transfer speeds of these memory cards and also they are identical in their technical specifications as well. All SDHC and SDXC class 10 memory cards that we are manufacturing are UHS-1 also."

  • The statement above is TRUE as far as I can tell - no glaring marketing lies which is refreshing

  • 1. equivalent = is similar but different, so Sandisk is technically correct

  • 2. All UHS-1 memory cards have 10MB/s of minimum data - TRUE . While UHS-1 can go as fast as 104mb/s ( in theory ), it still only guarantee the same 10mb/s in write speed under worst condition. Since its the same absolute 10mb/s minimum write speed (in their technical specifications) , Sandisk can argue that all their Class 10 card also qualify as USH-1 albeit at the worst possible qualification .

My Interpretation Summary of Sandisk Double Speak:

  • Yes, UHS-1 can be VERY FAST, or "should be" faster than most Class 10 SD cards

  • No, we will not guarantee it will out-perform most Class 10 SD cards

  • We CAN guarantee it'll write at a minimum of 10mb/s.... just like any other Class 10 cards

  • No, we CANNOT guarantee it'll write faster than most Class 10 SD cards

Take Apart what WIKIPEDIA actually said :

  • http://en.wikipedia.org/wiki/Secure_Digital#UHS_Speed_Class with emphasis added.

  • UHS-I cards , specified in SD Version 3.01, support a clock frequency of 100 MHz, which in four-bit transfer mode could transfer 50 MB/s. UHS-I cards declared as UHS104 also support a clock frequency of 208 MHz, which COULD transfer 104 MB/s. UHS-I is the only class for which products are currently available. Double data rate operation at 50 MHz ( DDR50 ) is also specified in Version 3.01, and is mandatory for microSDHC and microSDXC cards labeled as UHS-I . In this mode, four bits are transferred when the clock signal rises and another four bits when it falls, transferring an entire byte on each full clock cycle.

  • " COULD transfer 104 MB/s - the keyword here is COULD. In reality, you're never see the theoretical 104mb/s. The maximum Toms Hardware could push a USH-1 card is around 79mb/s, using extremely fast CPU to push write speed + a USB 3.0 card reader

  • " DDR50 is the (only) mandatory requirement for UHS-I labels . Apparently any Chinese SD card maker who use DDR50 can technically qualify in labeling their SD card UHS-I as long as it is using the Double Data Rate 50mhz rather than the traditional SDRAM.

WHO IS AT FAULT?

  • personally, I blamed the SD ASSOCIATION for creating such a lax standard

  • SD.A need to demand a minimum writing speed (like it did with SD/SDHC cards), but is unwilling to do so caving to manufacture's pressure for marketing flexibility (i.e. LIES)

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Jim Holloman
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Re: Well put. Thank you.
In reply to 007peter, Jun 15, 2012

Well put. Thank you.

I just discovered some SanDisk cards on Amazon that are labeled with both an "I' and the "UHS" with a '1' in it and with a labeled speed of 95MB/s. I don't know if the 95MB/s means it is guaranteed to be able to continuous read at 95MB/s or not. For example:

http://www.amazon.com/SanDisk-Extreme-UHS-1-Memory-SDSDXPA-008G-AFFP/dp/B007NDL542/ref=sr_1_3?s=electronics&ie=UTF8&qid=1339799255&sr=1-3&keywords=sandisk+uhs-1

Do you have any experience with Transcend SD UHS-1cards? IF so, what is your opinion of them?

The Transcend cards appear to be a lower price point than the SanDisk cards. I ordered one 8 GB Transcend card (labeled UHS-1) for use in an Olympus TG-1 and got a "Card Error" on the first use after about 40 photos -- fortunately, even before I even left the house. That is the first time I have experienced a "Card error" since I stated shooting with an E-1. The card was sent back to Amazon today.

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Crimguy
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Re: Well put. Thank you.
In reply to Jim Holloman, Jun 15, 2012

the 95mb/s is theoretical. Some tests I saw online indicated it occasionally jumped into the 80mb/s range.

I have the Sandisk Extreme Pro 16gb, which is their "95mb/s" card. It is indeed very fast, but I have a feeling I could have very similar results with their 45mb/s Extreme card, which was $20 cheaper or so ($50 vs. $29).

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Crimguy
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Re: Well put. Thank you.
In reply to Crimguy, Jun 15, 2012

And incidentally, while the write times to the card are very fast, its only at limited times that it proves useful. Where i notice a consistently nice jump is in transferring the files to my computer, which doesn't really mean that much to me (although it should I guess).

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Panda9
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Re: Well put. Thank you.
In reply to Crimguy, Jun 15, 2012

I own two Sandisk SDHC UHS-1 95Mb/s cards and tested them against a Transcend Class 10 30MB/s card and got the following results that I posted in a thread a couple weeks ago:

http://forums.dpreview.com/forums/read.asp?forum=1041&message=41627673

Regardless of the labeling or hype, I am seeing a real-world significant speed-up in write times in my E-M5.

Note that Sandisk sells several UHS-1 cards, labeled with speeds (95Mb/s, 45Mb/s, 30Mb/s). I do not own nor tested the 45 or 30 cards.

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teohyc
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Re: Well put. Thank you.
In reply to Jim Holloman, Jun 15, 2012

Jim Holloman wrote:

Well put. Thank you.

I just discovered some SanDisk cards on Amazon that are labeled with both an "I' and the "UHS" with a '1' in it and with a labeled speed of 95MB/s. I don't know if the 95MB/s means it is guaranteed to be able to continuous read at 95MB/s or not. For example:

http://www.amazon.com/SanDisk-Extreme-UHS-1-Memory-SDSDXPA-008G-AFFP/dp/B007NDL542/ref=sr_1_3?s=electronics&ie=UTF8&qid=1339799255&sr=1-3&keywords=sandisk+uhs-1

Do you have any experience with Transcend SD UHS-1cards? IF so, what is your opinion of them?

You mean the Transcend Class 10 UHS cards?

Those are quite fast actually. See some comparison here:
http://daisukiphoto.com/content/best-memory-card-mirrorless-cameras

Anyway, with a UHS card, your device needs to be UHS compatible to take advantage of the speed.

E.g. Panasonic GH2 can only take advantage of 45MB/s card and not the 95MB/s one.

A UHS can write to a slow Class 10 speed, but not the other way round for the Class 10.

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ayt
ayt
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that is indeed messy
In reply to Jim Holloman, Jun 16, 2012

the card I have performs fast enough for my needs and I haven't found myself waiting on the card when I wanted to shoot. it's too bad we cannot rely on the specs and standards to know what sort of performance we are buying, and have to resort to external benchmarks or self-tests.

I bought my card based on price, which was IIRC ~5000 yen at a discount shop in Akihabara. pretty cheap for a 64GB SDXC. it is a greenhouse branded 64GB SDXC class 10 U1 I. while there seems to be more space available on the card label for more random speed class identifiers if the SD association wants to confuse us more, it has all the markings it could currently have.

rather than starting work on a new UHS-2 standard when UHS-1 is still developing, I wish they'd focus on making things easier for consumers. make some standard class ratings higher than 10. we have cards that do 20, 30, 45, 95 MBps, yet they are all class 10. and maybe a sub-class for the new UHS stuff with minimum speeds.

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John Mason
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real life tests
In reply to Jim Holloman, Jun 16, 2012

In looking at various real life tests on the web, some class 10 cards out-perform uhs-i cards and visa versa.

I ended up getting the Sandisk Extreme Pro as these seem to be the fastest for an SD card right now regardless of the technical specs.

So who knows if class 10 = uhs i

google up some real life tests - the bottom line speeds are all over the map in spite of the marketing rating of the cards.
--
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szlevi
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Sandisk Extreme Pro *IS* their UHS-1 card...
In reply to Jim Holloman, Jun 16, 2012

...and the 32GB I just bought this week in B&H is a lot faster in my OM-D than my Class 10 cards.

Jim Holloman wrote:

The following is an exchange with SanDisk regarding UHS SD cards. Reach your own conclusion.

I purchased this SanDisk UHS-1 SC Card for use in the OM-D:
http://www.amazon.com/gp/product/B007B5RIN4/ref=oh_details_o01_s00_i00

I have received the card, and there no mention of "UHS" on the label nor on the package. Nor, does it have a 'U' letter with a '1' inside of it as you find on Transcend SD cards (number contained within a U-shape). It does have a simple 'I' on the label, but by itself such a mark has no significance.

So, I sent a message to Sanddisk. This is part of the reply:

"Please be informed that UHS-1 (Ultra high speed) is equivalent to class 10. All UHS-1 memory cards have 10MB/s of minimum data transfer speed same as a class 10 card. There is no difference in the data transfer speeds of these memory cards and also they are identical in their technical specifications as well. All SDHC and SDXC class 10 memory cards that we are manufacturing are UHS-1 also."

The last statement may be valid. I question the other assertions.

This is from:
http://en.wikipedia.org/wiki/Secure_Digital#UHS_Speed_Class with emphasis added.

"UHS Speed Class

Cards that comply with UHS show UHS-I or UHS-II ==> on the label

Also:

"UHS-II cards, to be defined in Version 4.0, further raise the data transfer rate to a theoretical maximum of 312 MB/s"

This is from: http://transcend-info.com/Press/DrT.asp?LangNo=0&axn=Detail&PrsNo=115&NewsKeyWd=&Func1No=3&Func2No=211

"...UHS-I is the fastest category of card available today with a bus interface speed of up to 104 MB/s, while UHS-II is expected to reach 300 MB/s..."

This is from:
http://sdcard-speed-guide.articles.r-tt.com/

"Beyond Class 10 is the UHS Speed Class. UHS stands for ultra high speed and includes cards that have speeds up to 312 Mb/s. The UHS speed class logo includes a number contained within a U-shape. Currently, there is only one UHS speed class: UHS Speed Class 1, which is designed for the UHS bus interface. Cards in this class will usually be noted as SDHC UHS-I or SDXC UHS-I."

This is from: http://news.thomasnet.com/fullstory/Class-10-UHS-I-Memory-Cards-aid-full-HD-video-capture-607479

"The new Class 10 SDHC UHS-I cards boast a staggering four times faster transfer rate compared to Class 10 alone, realizing transfer speeds of up to 85MB/s when paired with advanced UHS-I compatible devices."

-- hide signature --

UHS-II cards will clearly not be the same as Class 10 cards. So, to avoid such confusion, please consider labeling all of your UHS cards as either UHS-1 or UHS-II cards.

The Sandisk SD card that I purchased is a Class 10. It shows a maximum transfer of 30 MB/s (for reading only, write speed slower) -- not 85MB/s.

Thus, the information you give me is inconsistent with the information I find on various sources on the Internet.

This information is to be posted at:
http://forums.dpreview.com/forums/forum.asp?forum=1041

In a message titled "Class 10 vs UHS". Please feel free to respond to the message.

-- hide signature --

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GodSpeaks
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Re: Sandisk is at least HONEST, the TRUTH about MARKETING
In reply to 007peter, Jun 16, 2012

007peter wrote:

WHO IS AT FAULT?

  • personally, I blamed the SD ASSOCIATION for creating such a lax standard

  • SD.A need to demand a minimum writing speed (like it did with SD/SDHC cards), but is unwilling to do so caving to manufacture's pressure for marketing flexibility (i.e. LIES)

This is exactly the same BS we went through with USB (1.0/1.1/2.0). The standards committee decided to revise the meaning of USB1/USB2 so that the marketing department could claim devices were USB2, when in fact, they were not.

No care was given to the consumer, who was left to his own devices to ferrit out the truth regarding compatability.

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