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SanDisk CompactFlash read/write speeds and UDMA information

Are SanDisk CompactFlash cards UDMA enabled?

There are several factors that affect maximum read and write speeds of devices using CompactFlash cards. The most important factor is the communication method between the host device and the memory card. There are two communication protocols that CompactFlash cards use to operate: PIO (Programmed Input/Output) mode and UDMA (Ultra Direct Memory Access) mode. The development of CompactFlash moved from the slower PIO technology to adding the improved UDMA technology.

CompactFlash cards originally only supported PIO modes. CompactFlash options for UDMA were added beginning in 2003. By 2005 SanDisk was producing high performance Compact Flash with UDMA support. Camera manufacturers were also adding support for UDMA during this time. In order to take advantage of the CompactFlash card maximum speed, your camera or card reader will need to support the same UDMA modes. If not, the card will operate using the lower UDMA or PIO modes that are supported by your camera or card reader.

Most high end model cameras (DSLR and Camcorders) that use CompactFlash have supported UDMA since 2006-2007. You will need to check your specific camera user manual to verify that it supports UDMA.

The list below shows the maximum theoretical performance capabilities for PIO and UDMA technology.

PIO
Mode 6 - 25MB/s
Mode 5 - 20MB/s
Mode 4 - 16.7MB/s
Mode 3 – 11.1MB/s
Mode 2 – 8.3MB/s
Mode 1 – 5.2MB/s

UDMA
Mode 7 - 166MB/s
Mode 6 - 133MB/s
Mode 5 - 100MB/s
Mode 4 - 66.7 MB/s
Mode 3 - 44.4MB/s
Mode 2 - 33.3MB/s
Mode 1 - 25MB/s

Also, see SanDisk CompactFlash cards that are UDMA enabled.

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