SD Cards, Speed Ratings, and Card Readers/Writers

Hello all,

Being a photographer myself, it really angers me to see all these cards touting speed ratings like 40x, 66x, 80x, 133x, 150x and others not having any at all. Sometimes it makes life hard when buying memory cards to make a decision - because it might turn out that these speed ratings are all a LIE! I’ve had some cards that clearly are slower than what they claim to be - and have some 66x cards outperform 133x cards in my camera.

Then comes card readers, most of which I’ve tried never break the 7MB/s barrier for read or write regardless of card - claims of 20Mb/s never seem to show up. Sort of makes no sense if a high speed card doesn’t “show off” the speed.

It also really causes me problems to see that 150x SD cards seem to have compatibility issues with some devices e.g. PDA’s which fail to format/recognise them. Also 4GB SD cards which are out of standard and some MMC Cards that corrupt themselves and lock up and die!

SD Cards seem all so fragile, the plastic doesn’t last - i’ve broken two already and this is just so frustrating.

Just my experiences on memory cards, ever so frustrating for me … feel free to share your experiences (also trying to wake up a seemingly dead and quiet place in the forum).

I recently attended the Flash Memory Summit where similar concerns were voiced. Unfortunately, reliability was not addressed as much as capacity and speed. I am told that flash memory will have wider role to play with new operating systems. This might trigger more widespread recognition of the need for reliability.

Mmmm yes reliability - I’ve killed several CF cards - think i’ve depleted their write cycles because they “self corrupt”… pictures start corrupting a few hours after they’re taken and the cards had Samsung / Toshiba flash modules in them. Heavily used though. Had other cards that just flat out refuse to format / recognise in some devices and or stop working after a short while. Had some erase themselves after a few inserts/removals which was disasterous. So many bad experiences, but luckily they don’t happen too often.

Had issues too with 1Gb Corsair 133x SD card not running faster than 1.5Mb/s on the ICSI card reader I have. The 2Gb Kingmax 150x SD card not working in a Kodak CX4300 or my XDAII Mini. 1Gb Kingmax Platinum 66x SD Card not working with the Omni Digital Media Player … so many problems with SD.

But there is one durable design - the 1Gb Kingmax Platinum I’ve used the most - has a ceramic “package” that i can’t seem to damage - works a treat but I can’t seem to find them - with falling prices, most retailers are resorting to selling the KingDisks which are plastic :frowning:

Just thought I’d share my experiences.

I rarely take the SD card out of my camera. I usually get my pictures by plugging a USB cable into my camera. I also have a cradle I can set my camera into to get the pictures.

I haven’t had any problems with my SD cards, but I don’t use mine as much as you do.

A magazine article recently tested several different cards from well known manufacturers and also generic (cheaper/budget) cards, they found no reason to buy expensive cards claiming high speeds as the speed is governed by how quick the camera electronics can send the information to the card.

True for the most part. However, a lot of generic cards have had poor quality control, failing after just a few uses on average.

On the other hand, some so-called “high-speed” cards from some brands are equal in price to or less expensive than some unrated cards (read: those cards which do not claim a speed rating) from other brands. But high-speed cards in general are needed only if you’re doing continuous, rapid-sequence shooting for more than just a few frames on some higher-end compacts or SLR’s, where the average unrated card will cause the camera to start lagging after just a few shots. (Most low-end compacts limit the photographer to single shots at a time or sequential shooting of no more than a few frames.)

At any rate, under no circumstance should the photographer wait for more than about 10 seconds or so to take the next shot even with an “unrated” card. However, if a given card is so slow that the photographer needs to wait several minutes between shots, then either the card is defective or (less likely) the card is severely mismatched to the camera.

NAND technologies are evolving very fast. 180x SD cards are reasonably priced nowadays.

As for reliability… I believe experts know a little better. Major HDD manufacturers including Seagate and Samsung want to make flash-magnetic hybrid HDD. Such hybrid drives will not only be faster but also more reliable. Intel, Microsoft, AMD, many motherboard manufacturers, etc. are also going in that direction.

Two broken SD cards, and you call them fragile… exactly how do you know NAND flash chips or SD memory specifications are fragile? There must be reasons why your cards died or degraded or whatever.

Try some of the very recently made 180x or faster SD cards. Test the speeds on your PC, not camera. It should be at least 20MB/s. Though that’s still not up to the advertisement, it’s much better than what the ODD industry does which makes 20x DVD (which is 27.5MB/s) writers that are actually slower than those 180x SD cards.

The main problem that i have is that the memory card reader controllers [from more than 4 different brands of readers] seem not to transfer faster than 7mb/s - i don’t particularly like how we are buying faster cards, yet most reader/writers seem to limit the speed.

As to the fragility - i think the random corruption issue after some many uses even with lexar media cards are just to do with the memory exceeding the overwrite limits and not registering all data in a clear manner. The breakage of the card shell is not a testamant to the fragility of the memory itself but the shell itself seems to be the problem. The manufacturers of some cards seem to have plastic that doesn’t handle any flexing - which is inevitable when you swap cards four or five times a day - that’s why they break - because the plastic is fragile. Meanwhile a PIP card from kingmax which is hard like ceramic … doesn’t break. That’s why.

What I meant is that such things are not the inherent “fragility” of NAND flash chips. I heard “SLC (Single Level Cell)” cards are a little faster and more reliable than “MLC (Multi Level Cell)” cards. The chip speed and reliability are much more important than the durability of the case plastic as the latter can be improved very easily.


For independent speeds test see [Link to commercial site removed]

Not a complete list but better than you will find anywhere else, they are actual tests not figures pulled for thin air.

Some cheap cards are very good and some branded ones are just rubbish both in terms of performance and reliability.


[Commercial link removed from post above]

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I own four different kinds of SD cards all rated 60x or 66x and 1GB and I tested them all for WRITE speed. The testing was performed by dividing the time it takes to fill the entire card with zeros and dividing by the time it took. I tested each card twice and averaged out, however both attempts were very close for each card.

SanDisk Ultra II

ATP 1GB (66x) (generic)

Corsair 1GB (60x)

Corsair 1GB (133x)
5.43MB/s pretty weak for 133x if you ask me…
The Corsair 1GB is slow as heck and my camera stalls on “continous recording” (2.3 fps) mode.

The generic “ATP” brand did just as well as SanDisk, bu that card once failed mysterious couple months ago and I had to get it replaced.

Actually, the ratings on the Corsair cards are for the READ speed. Their write speeds are significantly slower than implied by their 60X or 133X ratings: The “60X” card’s rated write speed is only 40X, while the “133X” card’s rated write speed is only 100X. In fact, my 2GB “unrated” PNY SD card did just as well as the “60X” Corsair SD card in write speed.

well … errr … I think the card-reader/writer might be limiting performance, because I had write speeds ~7-8Mb/s with my fastest reader/writer. Most reader writers top out at 6Mb/s - no where near 100x … hence my frustration with them.

The corsair only read at 1.5Mb/s with one of my readers - compatibility issue i’d say.

Which card reader/writer did you use?

Also, did you use the scale “1GB = 1,000MB” or “1GB = 1,024MB”?

Using the decimal GB/MB scale (1,000,000 bytes = 1MB; 1,000,000,000 bytes = 1,000MB = 1GB), here are my results testing a variety of different size cards using the “zero-fill” method with either a “60X” write speed rating or no speed rating with a Sandisk 12-in-1 reader/writer:

SanDisk Ultra II 2GB (60X)

PNY 2GB (no speed rating)

Lexar Platinum II 1GB (60x)

Sandisk 1GB (no speed rating)

Sandisk 256MB (no speed rating)
3.39MB/s That’s S L O W, but pretty typical of a smaller-capacity SD card…