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Product Review: Transcend High Capacity Compact Flash Cards
By
Michael Fulks
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News Flash!!!!
......Transcend Press Release (Transcend Information, Inc.) |
Incredible, isn't it? When I first started playing with computers in 1980, machines with 16K, 32K, or 64K RAM memory were the norm. Programs were stored on floppy disks read from one drive while data was stored to a disk on a second. For the average computer owner, a megabyte of storage was beyond imagination.
In the middle 80’s, I bought my first IBM computer, a 286 machine. I don’t remember how much RAM it had, but the hard drive was a whopping 10 megabytes! When I could finally afford the $400 price tag, I sprang for a 20 megabyte hard drive and marveled at the amount of data I could store.
When I started going digital with my photography in the early 90’s, the biggest drive I could buy was 256 MB. I soon found that I needed three of them to do image work. This machine also had 64MB of RAM, and the memory cards cost me $1000.
I mention all of this to emphasize the enormous advances we have seen in computer speed and power in the past ten years and to put the amazing amount of memory that can now be stored on Compact Flash, Smart cards, and the like into perspective. The idea that 4 GB of data can now be stored on a device that has no moving parts and is no larger than a 35mm slide (a little thicker, of course) is simply amazing.
What is Flash Memory?
Before we begin this month’s product review of Compact Flash Cards by Transcend, let's review some background on these little marvels. Unlike storing ones and zeroes on a rotating platter, as is done on a hard drive, data are stored in memory cells. This is very similar to the way data are stored in the RAM of your computer, with one key difference. The RAM on a compact flash is “non-volatile.” These means that the memory cells remember the data stored even when they're removed from the source of power, such as your card reader or camera. They remember the data until they're instructed to do otherwise, unlike the RAM in your computer which evaporates when the power goes off. Also, because there are no moving parts, the flash card is very durable. Imagine dropping a hard drive from a second floor window. I don’t have to tell you the result, yet flash cards have been dropped even farther without damage. This type of memory is called “flash memory.”
Single Level Cell vs. Multi Level Cell NAND Flash Memory
Flash memory is stored on tiny memory chips. The density and the size of the chips determine how much memory the flash card can store. As manufacturers discover how to make these chips smaller and how to pack more of them into a single unit, the capacity of the flash cards continues to rise. NAND Flash ICs are the types of chips from which most Flash memory, including Compact Flash Cards, are made. NAND Flash ICs have an advantage over other types of Flash ICs with regard to data storage.
Here's where knowing what kind of memory you're using is important. There are two types of NAND Flash memory architectures: Single-Level Cell (SLC) and Multi-Level Cell (MLC). SLC NAND Flash is the higher performing technology that is used to enable streaming video and Internet capability in handheld electronics such as 3G cell phones, PDAs, digital still /video cameras and MP3 players, etc. MLC NAND Flash, on the other hand, is appropriate for short-term, price-sensitive applications, such as voice recorders in which streaming video is not required. SLC NAND Flash’s architecture is straightforward, providing a significant performance advantage over MLC NAND Flash, whose architecture is convoluted. SLC NAND Flash ICs have one bit of data stored per memory cell and two states: erased (1) or programmed (0). MLC NAND Flash ICs have two bits of data stored per memory cell and four states: erased (11), two thirds (10), one third (01) or programmed (00). The complex architecture of MLC NAND Flash is a performance disadvantage when compared to SLC NAND Flash. 1
With only two states and one bit of data stored, SLC NAND Flash’s Control Logic is able to conserve energy when managing the electrical charge during operations. This is why, during the program operation, SLC NAND Flash is faster than MLC NAND Flash.
Since MLC NAND Flash has four states and two bits of data stored, it must expend more energy to manage the electrical charge during operations. Applying higher voltage to program MLC NAND Flash degrades its memory cell characteristics. And, with smaller margins, the chances of an incorrect reading are higher. Plus, due to leakage and other effects, the logic level of the cell may change. MLC NAND Flash must compensate with enhanced EDC (Error Detection and Correction).
Because MLC chip technology allows two data bits to be stored in each memory cell versus one data bit for SLC chip technology, MLC NAND Flash ICs (chips) can have double the memory capacity for the same size chip as an SLC chip. MLC chips are, therefore, lower in cost for the same capacity, but performance for MLC chips is poorer. For example, a performance study by Samsung Electronics, a major memory manufacturer, which evaluated SLC chips versus MLC chips observed that MLC chips provided only 10K program/erase cycles, while SLC chips provided up to 100K program/erase cycles. This indicates that a SLC chip has durability ten times greater than a MLC chip. In addition, SLC chips performed 300% faster than MLC chips in write mode, and 43% faster than MLC chips in read mode. Although the use of MLC chips in Flash memory cards can save up to 30% in costs for manufacturers, it's 60% lower performance level in comparison with SLC chips doesn’t provide much of a benefit for customers. 2
Some major CompactFlash Card manufacturers--Toshiba, SanDisk, etc.--make two different types of CompactFlash product lines. One type of CompactFlash Card products is assembled with NAND Flash ICs (chips) manufactured using MLC (Multi-Level-Cell) based chip technology, while the other is made with chips manufactured using SLC (Single-Level-Cell) based chip technology. The MLC based chip technology is a low-cost Flash solution, but a CompactFlash Card made with MLC chips has a lower write speed, higher power consumption, and inferior durability to a CompactFlash Card made with SLC chips. For example, if you compare the datasheets for Toshiba's MLC based CompactFlash Cards to Toshiba's SLC based CompactFlash Cards, you find that the MLC based cards have a 10X write speed (1.5Mbyte/sec), while the SLC based cards have a write speed of up to 22X (3.2Mbyte/sec for 64MB to 512MB capacity cards; however, 8MB to 48MB capacity cards still function at only 10X). Also, the MLC based cards have a 15% higher power consumption than the SLC based cards, a drawback for use in portable devices like Digital Still Cameras or PDAs where battery-life is a critical performance satisfaction issue. 3
In contrast to other manufactures, Transcend insists on using only original SLC (Single-Level-Cell) NAND Flash chips that have a higher write speed, lower power consumption, and superior durability compared with CompactFlash cards made with MLC (Multi-Level-Cell) chips. Transcend Ultra Performance 45X CF cards can achieve a read speed of up to 8 MB/sec and a write speed of up to 6.6MB/sec, three to four times faster than a traditional CompactFlash Card.
The Brains of the Flash Card: The Controller
Each flash card needs a controller to tell it how to store the memory. The speed at which the card can store data is, in part, determined by the architecture of the controller. This often creates a bottle neck as this controller may interact differently with any given camera. Thus, a speedy card may be speedy with one camera, but offer no advantage over a slower card with another camera.
There are many CF labels out there, but you may be surprised to find out that the controllers are made by only a handful of companies. Thus, you may be buying Brand X CF card, but the controller is actually made by Hitachi or Toshiba. Transcend stands out amongst the field of CF labels in that it uses its own proprietary controller.
Here is something else to keep in mind: According to Rob Galbraith (see link below), cameras don't write their stream of zeros and ones randomly. Most, if not all, digital cameras use the DOS FAT16 file system as a way of keeping track of the location of those photos when writing those ones and zeroes to the card. This means the cards themselves have to be FAT16-formatted, regardless of whether they're hard drive or flash memory CompactFlash. Cards with capacities over 2GB must be formatted FAT32, a newer variant of the FAT file system that is not universally supported in older digital cameras (though camera models that accept CompactFlash Type II introduced from 2003 onwards will almost certainly be FAT32-capable).4
How fast is it?
You may have seen the marking on various Compact Flash cards indicating 4X, 16X, or 45X speeds, and wondered exactly what that referred to. By most standards, a single “x” is 150 KB/sec. Thus, a 4X card should be capable of transferring data at 600 KB/sec; likewise, a 16X card should handle 2400 KB/sec. Unfortunately, card manufacturers don't tell you how this number is computed, whether this is read or write, or what the device is that's doing the reading and writing. For example, most cameras below the professional level realize no advantage as one uses a faster and faster card. This seeming contradiction happens because the architecture of the camera/controller interface does not allow transfer rates over a certain level. As you upgrade your digital camera, you might be well advised to check out this particular aspect. With my Olympus E-10, I was unable to discern a difference between the Transcend 45X 256MB card and a 4X from another manufacturer by timing the amount of time it took to write from the camera’s buffer to the card. The E-10 can store six images in its buffer firing in a burst, beginning from the moment the shutter is pressed for the first image to the time the last of the images had written to the card as indicated by the flashing read/write LED. This testing procedure may not be the most sophisticated method possible, but it is very telling from a practical point of view. When we tested the card on other consumer digital cameras, we came to the same conclusion.
There are, however, cameras that do realize the faster speed of the higher speed cards. A very good source for information about the cameras that do can be found at: http://www.robgalbraith.com. This website is a wealth of information about many manufacturers and the results of speed testing with both camera-to-card and computer-to-card. You can see how various cameras interact with the most popular CF cards in regards to speed as well as how the various cards interact with a typical computer. Transcend products rank among the highest for speed in both areas.
So, is it worth it for the regular Joe to spend more for faster cards, when he does not own or can’t afford a camera that can take advantage of the faster speeds? Taking a look at the transfer speeds of card-to-computer helps answer this question. When you use the card in a reader, such as a USB 2.0 reader, the advantage becomes obvious. The faster card is a time-saver, especially when you're transferring the whole card to your computer’s hard drive. (I found that it makes much more sense to take the card out of my camera to download my images than to download them directly from the camera.)
The Transcend card 45X is also a time saver for me when I work with my local photo lab. There, customers can bring in their CF cards with the files they need to have printed. For a while, I was writing these to CD-RW. But now I find it more efficient to download my images to the CF card via the USB 2.0 card reader, take them to my lab where I download them to their computer via a self-service kiosk, and return home with my card. The 45X speed is obviously an advantage in this situation.
Obviously, for me the answer is straightforward. If you're using larger capacity cards, it makes sense to buy the faster cards because of the time you save in the transferring of files from card to computer or vice-versa. This conclusion, of course, assumes that you've invested in a good card reader hooked to your computer. If you only transfer images from your camera directly to your computer, it may not be worth it for you to pay the higher price.
Transcend cards are definitely worth considering if you're looking to buy a new card or upgrade to a higher capacity CF card. Their use of SLC chips for more reliability and speed, the 5 year warranty, and the price make them particularly attractive. You can purchase them directly from Transcend online store. Or consider the following:
http://www.newegg.com. Click on Flash Memory and then select Transcend from the list of manufacturers. (I think you're going to be floored by how reasonable even the high speed, high capacity cards are!)
Transcend Compact Flash Features
Fully compatible with CompactFlash
Association and PCMCIA card
standard
True Plug and Play
Low power consumption
Single Power Supply: 5V ± 10% or 3.3V ± 10%
Recommended operating temperature: 0ºC (32°F) to 70ºC (158°F)
Available Sizes: 128MB, 256MB, 512MB, 1GB, 2GB and 4GB
5-year warranty
Ordering Information
Transcend Part Number; Capacity
TS128MCF45; 128MB
TS256MCF45; 256
MBTS512MCF45; 512MB
TS1GCF45; 1GB
TS2GCF45; 2GB
TS4GCF45; 4GB
Company Overview: Transcending Expectations
(provided by Transcend)
Transcend was founded in 1988 by Mr. Peter Shu offering two products-the "JetMate" laser printer driver and the "KeyPro" software protection system. Our product lines have grown to include over 2,000 memory modules for a multitude of devices including desktops, notebook PCs, servers, workstations, digital still cameras, fax machines, video games, etc.
Transcend memory products are available for many kinds of proprietary equipment as well as for mass market PCs.
We opened offices around the world to gain access to world markets and to provide superior service to our customers. Offices were opened in the USA (1990), Germany (1992), The Netherlands (1996), Japan (1997), Hong Kong (2000), and China (2000). Transcend received ISO 9001 certification in 1997.
In the year 2000, Transcend introduced Double Data Rate (DDR) technology memory products and successfully launched Transcend's first retail stores. Transcend-Taipei held an Initial Public Offering on the Taiwan Stock Exchange Corporation in 2001. In 2002, we added a variety of graphics cards to the package of computer components that we design and manufacture and greatly expanded our line-up of Flash memory products and other peripherals. In 2003 we opened our new worldwide headquarters in our brand-new building in the NeiHu district of Taipei, Taiwan. We are also devoting great energy into developing a whole new line of storage products.
Today, Transcend is surging into the future embracing the latest technologies, anticipating new challenges, and seizing new opportunities.
References:
2. Ibid.
3. http://www.achieva.com.au/news_slcvsmlc.htm
4. http://www.robgalbraith.com/bins/multi_page.asp?cid=6007
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