SanDisk SDHC Ultra II or Extreme III card speed

I recently ordered a SanDisk 16GB Extreme III SDHC card (“30MB/sec”), thinking it might be faster than the SanDisk 16GB Ultra II SDHC card I already had. Think again.

The graph below, using the SanDisk MicroMate USB 2.0 reader shows that the cards perform all but identically, in spite of SanDisk’s claim of 30MB/sec for the Extreme III, twice the speed of the Ultra II. Now maybe with a different card reader the results would be better, but I like the extremely compact MicroMate reader and I’m not planning on buying another. Results in a camera might be better, but I don’t really have any issues with the Ultra II. Lesson: don’t assume faster is real until you test it.

Click for larger graph