Compact Flash Cards

Compact Flash memory, the storage media of digital cameras, MP3 players and PDA's is getting cheaper and available with greater storage capacities, currently up to 512MB. Generally, the trend has been to buy the cheapest suitable capacity available or just accept the brand offered as part of a bundle when buying gear. With this in mind, I was curious to see what, if any differences there were between brands and if paying more for Compact Flash brought any benefits. To satisfy my curiosity, I collected cards from three of the most common brands here in the UK. Crucial, a subsidiary of Micron, a world renowned brand of quality memory, Sandisk, another world famous manufacturer and OEM supplier, and finally Integral, a cost effective brand from Just Rams PLC. who supply memory to many leading brands including Micron.

Each card was subjected to three tests.

1. The card was installed in a Ricoh i500 camera and the time taken to record an uncompressed Tiff photograph was measured. The picture file was 6,331,784 bytes in size. The recording time was measured using a digital stop watch to record the "active" duration of the cameras recording led. The camera was tripod mounted so the same picture was taken every time. To minimise errors the test was repeated ten times and the average time calculated. Before starting each test, the cards were formatted in the camera to ensure consistent results.

2/3.Using a USB 2.0 card reader, the cards were written to and read from using the same uncompressed Tiff file and the time to complete the action was recorded. Again each test was conducted ten times and the average time noted.

The equivalent transfer rate in Kbytes/second was calculated from the times as was a "speed" rating for each card. Manufacturers speed rate their cards against floppy disc speed, similar to CD-ROM ratings. Hence a rating of 1x being 150 KB/s, 2x being 300KB/s etc.

Many manufacturers state that you can use their cards without formatting them first. Well this is true BUT my experience has shown that formatting the cards first can make an enormous difference to performance. The camera picture taking test proves this. When taking pictures using an unformatted card or a card formatted under Windows 2000, the resultant time to write to the card increased three fold for all the cards. I strongly recommend formatting the card in its intended device before use. Incidentally, the USB 2.0 tests did not seem to care how the card was formatted!

By default, Windows XP will format any CompactFlash card of 64MB or more with the FAT32 format. Digital cameras and other devices usually use the FAT (FAT16) format and can not operate with a FAT32 formatted card.

The results are presented below with the best performances highlighted in red.

Looking at the results it is obvious that there are differences between the cards, but what do they mean in real world terms?

Analysing the picture taking test results, there is over two seconds difference between the fastest card, Crucial, and the slowest, Integral. This will affect how soon after taking a picture the next one can be taken and may make the difference between capturing the moment and missing it forever! Here it does pay to have the fastest card in your camera. It is worth noting that these results are with the Ricoh i500 and different model of camera may well produce different results due to the various cameras electronics. I would suggest, that when shopping for a flash card, that you try and test them in your camera before deciding. This may sound impossible to do but any decent "real" camera shop should let you try before you buy.

The USB read test returned a similar result with the fastest card being Crucial followed by Sandisk and lastly Integral. Surprisingly The Crucial is nearly 1.5 times faster than the Sandisk which itself is 1.5 times faster than the Integral. Almost a 3x difference between the fastest and slowest. Quite a significant performance lead.

The USB write test provides the biggest surprise with the Sandisk outperforming the Crucial by 1.4x and the Integral by 1.78x. This is quite an appreciable difference, especially when using the larger capacity cards and transferring lots of data.