07-26-2004, 05:00 PM
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Executive Editor
Join Date: Aug 2006
Posts: 29,160
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Memory Card Shoot-Out: Four 512 MB Secure Digital Cards Compared
We live in a world of marketing buzz, where the letter "x" is thrown in front of a number to show how much faster something is, but how much of it is true? In the realm of flash memory cards, most vendors offer two or more types of cards: the regular version, and a professional version that's said to be much faster than the normal version of the card. I always thought that those "high speed" memory cards were something you could only take advantage of if you had a high-end professional camera, and that the extra top-end speed was wasted when used in a PDA, phone, or consumer-level device. Imagine my surprise when performing a test on a Pocket PC and I saw different numbers when using a high speed Sandisk memory card! This prompted me to do some further investigating, so I created a simple test to see how several cards from top vendors measure up against each other.
When it comes down to which card to buy, you'll be thinking about more than just speed. Other factors to consider include price, warranty, availability, and brand � this article will not address those issues. Instead, I'm focused completely on raw speed, and how the speed of the card relates to its overall value.
The Flash Cards Tested
Wanting to eliminate as many variables as possible, I focused on testing only 512 MB Secure Digital Cards. I requested cards from over half a dozen vendors, but only Sandisk, Simpletech, and Delkin responded to my request. Each vendor was asked to send samples of their currently shipping 512 MB SD cards, both the consumer level cards and their high-end professional cards (if applicable). Sandisk sent me their Ultra II card. I had already had a 512 MB consumer-level Sandisk card in my possession for a few days, and it was fully tested, but I lost my first batch of test data when Windows XP abruptly died on my laptop and I didn't have a backup (I know, I know�). Simpletech sent me a 512 MB SD card in a ProX package, but the label indicated it was their standard consumer-grade card. Testing confirmed that it was their consumer level card. Delkin sent me both their consumer grade eFilm card and their professional grade eFilm Pro card. The cards covered in this shoot-out are:
Sandisk 512 MB SD Ultra II
Simpletech 512 MB SD
Delkin eFilm 512 MB SD
Delkin eFilm Pro 512 MB SD
Testing Methodology
First, a word about the methodology I chose: Flash cards will perform differently based on what type of device is reading and writing to the card. So while a card might be blazing fast in a high-end digital camera, it might perform slowly in a phone. Thus, it's impossible to predict exact performance values across all devices. This article is focused on several constants, the only variable being the brand and type of card. The tests were performed using a Sandisk 6 in 1 USB 2.0 memory card reader connected to the USB 2.0 port on a Fujitsu P5010D laptop. No other programs were running on the laptop, and it was disconnected from the network to ensure maximum performance. No other USB devices were connected to any other port, and the laptop was connected to AC power and the CPU was set to maximum speed (900 mhz in this case).
Figure 1: HD_Speed in action
The software used to measure the speed was HD_Speed. Special thanks to Louis Solomon from Steelbytes for adding a timer to HD_Speed specifically for my use. Each test was run once for five minutes in length, so any speed blips would have been averaged out over time. It was for this reason that I only ran each test once � in initial repeated tests I saw zero variance in the final average after five minutes. Six tests were performed in total: three tests to benchmark how fast a device could read data from the card, and three tests to measure how fast a device could write data to the card. Each test utilized three sizes of data blocks: 256 KB, 1 MB, and 16 MB. I felt that these represented common scenarios: reading/writing files on a PDA (256 KB), taking and viewing photos (1 MB), and reading/writing RAW files in a high-end camera (16 MB). Those values are approximations of course, because every device will have different file sizes � my Canon EOS 300D takes JPEG images around 2 MB in size and the RAW images are 10 MB or so. The test sizes I used are a "best effort" approximation.
Results: Read 256 KB
Figure 2: 256 KB data read test.
Surprisingly, the consumer-grade Simpletech card pulled ahead of the pack with a speed of 6194 KB/s. Besting the more expensive pro card is no mean feat, but the slowest card in the pack, the Delkin, still hit 6092 KB/s. Bottom line: with small 256 KB files, all these cards are extremely fast and there's little significant difference between them.
WINNER: Simpletech
Results: Read 1000 KB (1 MB)
Figure 3: 1000 KB/s (1 MB) data read test.
This is where we start to see more significant gaps � the Delkin eFilm Pro, which trailed the Sandisk Ultra II in the 256 KB test, pulls ahead here with a score of 6246 KB/s. It's interesting to note that the consumer-grade Simpletech card is matching the more expensive Sandisk Ultra II card. The Delkin eFilm card is dead last, and when reading 1 MB files the difference between these cards starts to become more obvious.
WINNER: Delkin eFilm Pro
Results: Read 16000 KB (16 MB)
Figure 4: 16000 KB data read test.
This test proved to be the most interesting because as you can see, all the cards ranked the same. Each card proved to be equally capable of reading big 16 MB chunks of data. Why? I'm not entirely sure � at first glance I thought with such exacting speed matches (6552 KB/s) it was a limitation of the memory card reader, but at USB 2.0 speeds of 480 mbps, it should theoretically have a hard limit of 60 MB/s. Even if we factor in 50% overhead, we're still at 30 MB/s. So why did these cards top out at 6.5 MB/s? It's likely that the Sandisk USB 2.0 card reader and the ports on my laptop top out at 6552 KB/s, which is more than a little disappointing if that's the case. 6.5 MB/s is a long way from 60 MB/s! I'd be interested in hearing opinions from readers on this test. I'm going to acquire a different brand of memory card reader and will try this test again on my desktop computer to see if any differences are discovered.
WINNER: Four way tie under suspicious circumstances
Results: Write 256 KB
Figure 5: 256 KB/s data write test.
Once the results started to come in for the write tests, I knew this was where the differences would really show up. As you can tell from the chart above, the differences when writing 256 KB chunks of data are drastically different from reading 256 KB chunks. The consumer grade Delkin eFilm managed to write at 1714 KB/s, while the eFilm Pro card blasted away at 5052 KB/s. The speed crown on this test goes to the Sandisk Ultra II card at 5682 KB/s, but the Simpletech card did surprisingly well at 2764 KB/s.
WINNER: Sandisk Ultra II
Results: Write 1000 KB (1 MB)
Figure 6: 1000 KB/s (1 MB) data read test.
The results of the 1 MB data write test were similar to the 256 KB test, but the differences were slightly more pronounced. With the larger file size, the Sandisk Ultra actually increased in performance, breaking past the 6 MB/s mark and coming in at 6040 KB/s write speed. The Delkin eFilm Pro came next, scoring exactly the same as the previous test: 5052 KB/s. Both the Simpletech and Delkin cards were a little slower than the 256 KB test, hitting 2560 KB/s and 1638 KB/s respectively.
WINNER: Sandisk Ultra II
Results: Read 16000 KB (16 MB)
Figure 7: 16000 KB/s (16 MB) data read test.
This last test has some surprising results: across the board, all of the cards were faster at writing 16 MB data chunks than they were at writing 1 MB data chunks. The Sandisk Ultra II delivered on its name by dishing out a punishing 6552 KB/s. That number looks familiar doesn't it? It's the same number from the 16 MB read test, which leads me to believe that the Sandisk Ultra II card is actually faster than 6552 KB/s, but my setup is limiting the measurement of exactly how fast this card can go. The Delkin eFilm Pro clocked in at 5564 KB/s, a full half-megabyte faster than it pulled off on the 1 MB write test. The Simpletech increased over 1.2 MB/s and pounded the 16 MB data files away at 3726 KB/s. The Delkin eFilm card brought up the rear at 2286 KB/s, but that's still a good 0.6 MB/s faster than the 1 MB test. Assuming that the performance of writing 2-4 megabyte files is closer to the 1 MB test than it is to the 16 MB test, it seems that most of us aren't quite using our cards to their full speed potential with smaller files.
WINNER: Sandisk Ultra II
Overall Speed Results
Figure 8: Test results summary for all 512 MB SD cards.
The above chart indicates the cumulative total of each card � the KB/s speed of both the reading and writing tests were added together and the results show a clear winner: the Sandisk Ultra II is the fastest card overall and the winner of this shoot out. If you want the ultimate in performance, that's the card to get.
Best Bang for your Buck?
Once you factor in price, however, things get a little more complex. The Simpletech 512 MB SD card sells for as low as $98 USD in a Pricegrabber search. The Sandisk Ultra II sells for as low as $158 USD. The two Delkin cards list for as low as $97 and $222 (eFilm and eFilm Pro respectively). Let's have some fun with the math ;-) � I've never seen anyone do this before, so this might be a first. What happens when we take the overall KB/s ratings from the six tests, convert it to megabytes per second (MB/s) and compare it to the retail cost of the card? Here's what we get from lowest cost to highest cost:
$3.51 per MB/s � Simpletech 512 MB SD
$3.99 per MB/s � Delkin eFilm 512 MB SD
$4.26 per MB/s � Sandisk Ultra II 512 MB SD
$6.41 per MB/s � Delkin eFilm Pro 512 MB SD
Surprisingly, the best combination of value and price is the Simpletech card, followed by the Delkin eFilm card. The Sandisk is the performance champ, but nearly double the cost of the Simpletech card. If performance is your #1 need, the Sandisk Ultra II is the card you want. The Delkin eFilm Pro card is a decent performer, but it's 33% more expensive and 7% slower than the Sandisk Ultra II. You won't notice a 7% difference in performance, but you will notice a 33% price difference.
Final Thoughts...
Ultimately the card you pick should be based on how you'll use it. If the SD card is going into a Pocket PC or Smartphone, and will be primarily used for reading data stored on it (audio, video, programs), the read speed is more important than the write speed. If the card is going into a camera, however, write speed is paramount and you'll want the fastest card you can get your hands on even if it's more expensive.
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07-26-2004, 05:31 PM
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Theorist
Join Date: Oct 2003
Posts: 258
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I am glad I got a Sandisk Ultra II 512Mb. You want speed - its either Panasonic or Ultra II.
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07-26-2004, 05:50 PM
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Ponderer
Join Date: Dec 2004
Posts: 96
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Hi Jason,
Thanks for the review!
I'm curious about the reading of the 16Mb blocks of data. Instead of it being a possible limitation of your reader or your laptop, could it be that the software you used for testing is unable to record anything higher than the 6552 Kb/s that you noted? This is pure speculation on my part as I have no experience with HD_Speed.
Again, thanks for sharing! 
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07-26-2004, 05:52 PM
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Philosopher
Join Date: Aug 2006
Posts: 578
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Re: Memory Card Shoot-Out: Four 512 MB Secure Digital Cards Compared
Great article, Jason.
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07-26-2004, 06:04 PM
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Pontificator
Join Date: Aug 2006
Posts: 1,202
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It seems to me from a PocketPC perspective, the read time is more important than the write, since we are primarily storing programs, e-books, MP3, etc, and want fast access to them. In this case the SimpleTech card more than holds it's own, especially from a price perspective.
If you are looking for a fast card that you can use with both your PPC and your digital camera, then the write speeds of the Sandisk Ultra seem to make sense, since that's when the write speed will be most important.
It's always good to see comparisons like this, since it seems that SD card speeds can vary greatly from one manufacturer to the next.
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07-26-2004, 07:26 PM
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Pupil
Join Date: Aug 2002
Posts: 31
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I read a review somewhere that found a similar limitation on the Sandisk 6 in 1 card reader. Apparently it is not fully optimized for USB 2. Sandisk recommended switching up to their 8 in 1 reader to see the true potential throughputs. The article I read was comparing 1 GB CF cards.
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07-26-2004, 07:29 PM
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Intellectual
Join Date: Feb 2002
Posts: 253
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After getting BURNED badly with a Kingston 512MB Secure Digital card, I went on a search for a new one. I ened up getting a Transcend 45x 512MB Secure Digital card from NewEgg.com for $99 shipped. It simply SMOKES my Kingston card and the 512MB Panasonic card that I had before it (had corruption issues). I ran the same tests as Jason on my Transcend 512MB card with my internal 6-in-1 USB 2.0 reader on my desktop machine (connected with the internal USB 2.0 headers on my motherboard).
Athlon 64 3200+
Asrock K8SX
2GB PC3200 DDR SDRAM
Windows XP SP2 Build 2162
Western Digital Raptor 74GB
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07-26-2004, 07:30 PM
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Executive Editor
Join Date: Aug 2006
Posts: 29,160
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Quote:
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Originally Posted by Wingnut
I read a review somewhere that found a similar limitation on the Sandisk 6 in 1 card reader. Apparently it is not fully optimized for USB 2. Sandisk recommended switching up to their 8 in 1 reader to see the true potential throughputs. The article I read was comparing 1 GB CF cards.
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Hmm...interesting. Not fully optimized, eh? That's a bit strange. I'll contact them and see what they have to say...
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07-26-2004, 09:06 PM
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Theorist
Join Date: Mar 2003
Posts: 267
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Guys, if you guys are really concerned about speed in the desktop. Get a good job and buy a Firewire card reader. In my unnoficial timing copying\moving a file(forgot the size) is about 1 minute on a USB 2 drive and about 42 seconds on a firewire reader. they cost about $80 but you guys spend $600 on a PPC anyways 
Yah, Sandisk Ultras are the way to go. Because I have a digicam :mrgreen:
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07-27-2004, 12:13 AM
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Neophyte
Join Date: Aug 2003
Posts: 1
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This was great, but do I spend the extra money for a faster SD card for my Ipac? Is there a simple benchmark that we can use to measure performance on our PPC. Something that moves a 1 MB file from main memory to the SD card enough times to get a measure. It would be fascinating to see everyone's results.
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