Speed Reading: A Quick Look at Compact Flash Performance July 06, 2005 Alexis Dang

Introduction

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Today we take a quick look at a few compact flash cards and compact flash readers. The sure way to attract enthusiasts is to talk about speed and performance. Cards are often rated at 40x, 80x, or even 133x. We’ll discuss if all this even matters or where it does matter.

I believe that the only time faster flash cards are needed is in digital photography. Rob Galbraith, one of the web’s digital photography professionals, has an incredible database on the write performance of many flash cards in different digital cameras. You can definitely see a difference in performance between the different cards, but just as importantly between the cameras. Some equipment cannot take advantage of the extra speed, so you need to know if can get the speed that you paid for. We will not even attempt to do what Rob Galbraith has done, as that database is one of the best, unbiased reviews of memory card performance.

Faster writing to a card will allow your camera’s buffer to clear faster, reducing the time between shots and sometimes increasing your sustained burst shot sequence. If you have a camera that can record videos, you will need one of these higher performance cards to record at the maximum possible performance. Faster read times can also help with previewing images on the camera and with copying files to your hard drive.

Our emphasis in this article will be on the read speeds of these cards. Admittedly, this isn’t as glamorous as write speeds but important nevertheless. When you have to wait to copy a flash card to your laptop, you do not have access to the card, the laptop, and you are often too distracted to be taking pictures. For a time sensitive project, where every minute counts, you need to be able to transfer your images to your computer as fast as possible. One recent personal example was when I was trying to offload my 4GB card onto my laptop. It might have been like watching a pot boil, but it seemed to take forever. That’s when I decided to look into products that could have improved my productivity and made my life a little easier, hopefully without costing a fortune.

In browsing various internet retailers, you will find dozens of card readers wit h different card compatibilities, but there is rarely any mention of performance or speed of these readers. On closer scrutiny of some readers, they are simply USB 2.0 compliant, which means they will work in USB 2.0 ports, but will likely run at USB 1.1 speeds, that’s comparing 480mbs vs 12 mbs. The interesting thing is that the price of many of these card readers is similar, so how are you to decide which is the best, assuming you have a card format that most readers support.

The importance of card reading, we aren’t talking about the metaphysical, has not been lost on the professional photography community. Lexar has announced plans to ship a new series of compact flash card readers that will retail for about $100 each, although these were not shipping at the time of this review. It's impossible to compare all the card readers on the market, so on this first go around we'll be looking at a couple that are readily available. We tested 3 USB 2.0 readers and 1 firewire reader on an i875 motherboard running a Pentium 4 2.8ghz in Win XP.

What we will discuss is copying the files back to your computer using a few different card readers, to see if there is any performance difference.

The readers

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Meet the Cards

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These were the cards that I had available at the time of review, regrettable omissions include the Sandisk Ultra II and Extreme III cards, as well as the Lexar 80x WA cards, but those cards were not made available for review.

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Sandisk 256MB

This is our smallest capacity card in our roundup. It is one of the newer Sandisk cards with the latest packaging.

Corsair 512MB 80x

This card carries with it the fastest rating of all the cards tested. Corsair is relatively new to the flash memory game, as compared to their contributions to high performance system ram, but with their reputation on the line, we expect good things.

Toshiba 512MB SD

I use this in my Tungsten T3, so I thought I would throw it in to test. On my tungsten, it takes forever to write to the card, it is so slow that I have had to take my Avantgo channels off the card to quicken my hotsync times.

PQI 1GB

PQI usually makes the sale flash memory at Fry’s. They have a new version that says high-speed, this is their original series.

Kingston Elite Pro 1GB

This is Kingston’s premium line of flash memory. No claims on what “x” rating is to be expected from this

Corsair 4GB

You can’t find a bigger solid-state compact flash card that can be backed up on a single layer DVD. Back in the day, the pros would recommend 512MB cards since you could backup in the field and burn off a CD-R so you would have multiple redundancy. Today, with DVD-R capability in the field, the 4GB size is perfect. When dual layer media drops in price, we’ll be recommending 8GB flash cards.

Notably, this card is rated differently from hard drive capacity, in that it truly is 4 gigabytes and not 4 billion bytes. Using the hard drive naming scheme, it would be a 4.2GB flash card. Other flash cards tested use the hard drive naming scheme

Interestingly, the font of the printing on a few of these cards is virtually identical with very similar model naming schemes.

Performance

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We used HD Tach as a preliminary test of the read performance of these cards, then switched to Sandra SiSoft flash memory benchmark to test both read and write performance. I like the Sandra test suite because it tests many different file sizes on write and read speed. Both tests showed very consistent results.



Prior to our write tests, we re-formatted the cards within windows with standard cluster sizes, FAT32 for the 4GB card. With the 4GB card, going from 4kb to 32kb clusters did not have a significant effect on performance. We did not test the write performance with the Lexar card.

SiSoft Sandra

Conclusion

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More surprising is that the read performance of these flash cards isn’t too different. It may be because of the limitations of our card readers or equipment. Looking at Rob Galbraith’s testing, we see that most cards are pretty similar in speed, until you get to the Sandisk Ultra II or Extreme series, or the write accelerated Lexar cards, as with everything there is a bell curve distribution. One thing to note that with extensive use of these cards in a Canon 20D, Canon Digital Rebel, and Canon D30, we never experienced any lost images that have been reported with the Lexar cards.

Unfortunately, we did not see much correlation in the advertised read speeds of the cards and their performance in the readers, with good performance all around. A word of caution regarding 40x vs 60x vs 80x cards, some manufacturers define 1x at 150kb/s, others as 176kb/s. We got real world read tests of around 40x on all of our cards, I would say that this is pretty impressive. The newest Sandisk Extreme cards will support a new method for reading that is available on Sandisk readers with the “ESP” logo on the box. The model numbers for the improved readers and old readers are the same.

Based upon these results, taken in context with the previous publications on this matter, we would recommend choosing cards based upon capacity rather than advertised performance, unless you are getting the substantially more expensive Sandisk UItra II, Extreme, or write accelerated Lexar cards. We were hoping that the Corsair 80x and the Kingston Elite Pro would be better performers. In our informal write tests on the Canon 20D, we did not see a palpable increase in performance, even with the Corsair 80x card. Another big surprise was the read performance of the cheapest card, the Sandisk 256MB card. It may be that smaller cards are a little faster since there is less memory to access.

We hope to expand on these informal tests with more flash cards and readers in the future. With the increasing number of available options in these products, we hope to be able to give you some guidance beyond marketing hype.