Rob galbraith has posted the CF memory card write speeds of the Canon EOS 5d. The data in the test was derived by timing how long it took the Canon EOS 5D to write out 20 Large Fine JPEG and 7 RAW .CR2 photos to the card. Timing commenced when the camera’s card status light illuminated, and stopped when the light went out. Each test cycle was performed 3 times (if the card’s capacity allowed for that) to ensure accurate results.

For example, the SanDisk Extreme III 1GB SanDisk has a write speed of 6.194MB/sec at Large Fine JPEG format and 7.390MB/sec at RAW format. The SanDisk Extreme III 2GB SanDisk has a write speed of 6.197MB/sec at Large Fine JPEG format and 7.459MB/sec at RAW format.

Website : CompactFlash Performance Database for 5D