SD cards are used as supplemental memory in many mobile devices. Most people are concerned only with the size of the card (how many megabytes or gigabytes it will hold), but the speed and quality of the card is just as important. A "fast card" is one that will read and write data to the card very fast and consistently. Should I really care? Yes.

One of the real pluses of a handheld, is the response time. When I turn on my Treo Smartphone or open an application, the response time is very short. I'm ready to go in seconds. It is not like turning on my desktop and waiting, for what seems like forever, while it boots. The same holds true for writing and reading to an SD card. A fast card will read and write much more efficiently so the waiting time is less and your experience more positive. Some applications, like audio that I work with, write very large files and a fast card is a requirement for a good experience. A slow card will miss bits of data so the resulting playback sounds choppy and plays faster than the actual recording. A really bad card misses so much data that the recording can't be understood. Most cards can read data from the card better than they write data to the card, so the write speed is usually the critical factor.

Audacity Audio distributes a free utility, CardSpeed, to help you test your SD card speed. It is available for both the Palm and Pocket PC OS. Here is a link. http://www.audacityaudio.com/vfst.htm. More about how to use it later. I have used CardSpeed to show a comparison of the best card I have ever used, a Kingston Elite Pro 50X 512MB card (Panasonic is the real manufacturer) and an old SanDisk 64 MB nondescript card that I knew was pretty bad (Toshiba is the manufacturer). I ran 4 tests of each card on my Treo 650 and then 4 tests of each on my Treo 600. You will see that not only the SD card makes a big difference, but the Card / hardware combination does as well.

The CardSpeed test performs three tests in sequence and logs the results. It writes 32 bits of data to the card, then writes a block of 8kb, and then reads that block back. The results of each are logged and the overall time is displayed. Finally, it makes an evaluation of how fast the card performs. The test results follow. I have displayed the best and worst of the four tests based on the write 8kb speed (The most critical test for writing large blocks of data). The tests were run with full cards.

Treo 650 with Kingston Elite Pro 50X 512 MB SD card (Panasonic).

Treo 650 with old SanDisk 64 MB SD card (Toshiba).

Not much change between the four tests with the same card and hardware, but the two cards are dramatically different. Now, I ran the same test with the same cards on a Treo 600.

Treo 600 with Kingston Elite Pro 50X 512 MB SD card (Panasonic).

Treo 600 with old SanDisk 64 MB SD card (Toshiba).

As you can see the hardware makes as big of a difference as the card itself. The best hardware with the best card was 22+ times faster (based on Write 8 kb test) than the worst hardware with the worst card. That definitely equates to a better user experience. I can speak from experience in the audio world that a bad card on a Treo 600 will create a bad experience. A good card makes a happy Audacity customer.

My goal in this paper is to make you aware of the difference between cards as well as how the hardware affects it, and then how to assure yourself that you purchase a good card.

If you are not a believer at this point, let me give you another example. I am inserting this example after completing this paper, but it completely took me by surprise. I just couldn't believe the results so I did three sets of tests to make sure of my results.

I recently bought a new Treo 700P from Palm when they first came out. As a promotion Palm included a Palm 1GB SD Card for free. When I got it, I tested it with CardSpeed as I always do. It tested quite poorly. I thought that it was just a cheap card that Palm was just trying to get rid of and I really never used it. It was just too slow for me. My Kingston Pro Elite was over 5 times as fast on our Write 8kb test.

As part of setting up our SD Card website, a colleague of mine pointed out that the Palm card was quite a good card. "No, you must be mistaken". He was looking at the results using a Treo 700W. We tested again together. The Palm card tested significantly better than my all time favorite card, the Kingston Pro Elite. I couldn't believe it. I need to add this to my article.

In preparation for this addition, I tested a third time, with confirming results. I tested the Treo 700P and the Treo 700W. These are sister products and very similar. I am testing a Kingston Pro Elite 50X 512 MB card against a Palm 1 GB card. All products were purchased within a six month period.

Using the Treo 700P, the Kingston card always tested excellent and the Palm card tested poorly. I ran all tests four times (the tests were pretty consistent) and averaged the results. The Kingston card was 511% faster. I then switched to the Treo 700W using the same cards with the same data on the cards. All tests returned excellent results, but the Kingston card was only 61% as fast as the Palm card. "Wow!"

Comparing cards really depends on the hardware you are testing with. That is why we offer this Educational site. Let me explore some other issues.

In my testing I always run the CardSpeed test 4 times. I do that for a specific reason. Some cards will be good on one or two tests and bad on the rest. The two cards I used were pretty consistent, but that is not always the case. A fast card with consistent results is the ideal.

In my testing I used cards that were nearly full. Usually an empty card will test faster than a full card. Again, it really depends on the card.

It is somewhat of a challenge to recommend a particular card brand because many manufacturers don't make their own cards. For instance the SanDisk was a Toshiba brand and the Kingston, a Panasonic brand.

I used to recommend the SanDisk Ultra II, but no longer do. I had tested one a couple of years ago (a 512 MB card) that was the fastest card around. I get complaints now about consistency (mainly with 1 GB Ultra II cards) and recently I have had three complaints about only being able to use part of the card. One went like this. I am trying to record and I can only get a file of 483 KB and then it stops. When I change the audio type I can get longer or shorter times, but still only 483 KB. This is using a card that has over 500 MB of free memory. After deleting some unused files, it solved the problem. I have had three similar complaints the past few months. They were all using the same card type, a SanDisk Ultra II 1 GB.

Usually, the newer cards are faster, bigger, and better than the older cards. My Kingston card is a 50X. This means the manufacturer is putting an emphasis on the speed of the card. Kingston offered a choice of a regular card or a 50X card. For a few more dollars, I gladly paid for the faster card. You really need to test the card in the hardware that you will be using. Our CardSpeed test is free and can be downloaded from this link http://www.audacityaudio.com/vfst.htm We offer a version for the Palm OS and a similar version for the Pocket PC. The best advice I can give is to try your SD card choice in the hardware you will be using it in. I know that is hard to do. That is the main reason for developing this Web site. You can post your CardSpeed results with specific hardware and cards so other users can learn from your experience and you can learn from theirs. The following links take you there Palm or Pocket PC.

If you really feel inspired to educate others, we invite you to post an editorial expressing your experience, opinion, and viewpoint. Others will learn from your experience.

Fred Clark represents Audacity Audio, the maker of the Audacity Voice Recorder / Dictation line of products. The Audacity Personal Voice Recorder targets the casual user needing to make notes for himself. The Audacity Professional Voice Recorder targets professionals with dictation needs and other professional users. Both products are easy to use and full featured. They are quality products.