SDHC class classification myth

Out of curiosity, we just checked with the write speed some of our Micro SD cards:

1) Transcend Micro SDHC, 8G, Class 6: 9.1MB
2) Sandisk Micro SDHC, 8G, Class 4: 14.9MB

The Sandisk card came with a tiny red reader (Like this), bought in Hong Kong

The speed test was carried out using the Sandisk reader in conjuction with the card benchmark software called "ATTO". The test was carried out in the same computer. Same test is done twice with different sequences to ensure data consistency.

(Results photos are coming soon) As the results showed, the "Class 4" Sandisk card performed far better than the Transcend's "Class 6" counterpart.

By definition, a Class 4 card should constantly have a write speed of 4MB/sec, and Class 6 card, 6MB/sec. Sandisk did a very well job on this.

To our surprise, the read/write speed of this tiny reader is, amazingly, faster than most of the internal card readers in our machines.