The flash memory cards from various manufacturers make claims of speed -- "Highspeed" from Kingston Memory, "40x" from Lexar (nee Media),
Faster flash memory cards cost more; do they outperform under real-world conditions? That's what I was wondering.
(Flash memory, despite its flashy name, is actually quite slow. It is much slower than the memory on your computer's motherboard, and much, much, much slower than the memory used by high-end graphics boards. To read how flash memory works, read "How Flash Memory Works".)
I devised this speed test for the Canon S1iS: (1) reformat each memory card; (2) turn on the camera's continuous shooting mode; (3) hold down the shutter button for a hundred or so photos; (4) and then examine the results. The same scene should be used for each test, so that the size of the JPG images is similar.
I don't have any recent super-duper-high-speed memory cards, but I do have IBM's MicroDrive. I was interested to see how it performs relative to the memory cards I do have.
IBM MicroDrive 1GB - 0.88 pictures/second
Kingston Highspeed 96MB - 1.51 pictures per second.
Lexar 4X 64MB - 1.44 pix/sec
Canon Hispeed 32MB (included with the S1is) - 1.52 pix/sec
Canon 16MB (included with the G1) - 1.48 pix/sec
Epson 8MB (included with the PC800) - 1.62 pix/sec
* The MicroDrive is half as fast as flash memory.
* The flash memories were roughly similar in speed.