From Transcend technical support:
SD150X Read 18MB/s Write 11MB/s
SDHC CLASS6 Read 18MB/s Write 12MB/s
SDHC CLASS2 Read 18MB/s Write 3MB/s
SD150X Read 18MB/s Write 11MB/s
SDHC CLASS6 Read 18MB/s Write 12MB/s
SDHC CLASS2 Read 18MB/s Write 3MB/s