SDHC hits 30MB/s with Sandisk Extreme III

Sandisk has announced the new Extreme III SDHC memory card which has hit the maximum 30MB/s for the SDHC specifications. It comes in 4,8 and 16GB. The extra speed should be a boon for large video file transfers. Now if they'd somehow get rid of the FAT32 4GB file limitation.

Sandisk has announced the new Extreme III SDHC memory card which has hit the maximum 30MB/s for the SDHC specifications.

This got me curious about compact flash, so I google and find (if I got this straight) that a recent revision of the CF specs went from 66 MB/sec to 133MB/sec for max interface data transfer rate. Cutting through the hype for ACTUAL rates is harder, for me anyway. This seems fairly solid:

CF also comes in four speeds; the original CF, CF High Speed (also known as CF+ or CF 2.0 or II) with a typical 10Mbytes/sec read and 9Mbytes/sec write, CF 3.0 (or III) with a typical 20Mbytes/sec read and write and CF 4.0 (or IV) with a typical 40Mbytes/sec read and write. Although the package size and connector for Compact Flash add to the manufacturing cost, the connector means CF has a wide, parallel, data bus and this is partly why the popular format has remained. It allows some CF cards to support Ultra Direct Memory Access (UDMA) for a 300X (45Mbytes/sec) transfer rate, providing the device they are plugged into supports UltraDMA, which some high-end digital cameras now do. In theory, revision 4.0 of the standard supports up to 133Mbytes/sec, and seek times for DMA-capable CF cards can beat those of a hard drive. Capacities range from 32MB up to 64GB and the cards themselves include a controller chip to perform wear mapping and filing system conversion.

So if these measures are comparable, the top CF rates are still ~30% faster than the top SDHC cards. True?

You are just comparing interface transfer rates. There's still flash behind those interfaces.

The CF specification is nothing more than the IDE specification mapped onto a smaller form factor. With the right cable, you could plug a CF straight into a PATA connector on a motherboard and boot from it. Yes, that's faster than the other flash card interfaces. It's also much bigger. IDE has gone over 100 MB/sec for a long time so it's no surprise that CF could do it. What's more interesting is getting a reader that goes that fast.

Flash cards have to have a controller that does wear leveling and remapping. No matter how fast the flash is it's possible to outrun that controller. These devices are small and low power so they can only be so fast.