[CovKid66]

I believe any cards over 2 GB are SDHC cards...although some of the earlier 4GB SD cards were simply not classified as SDHC.

Performance is measured by the class...not SD vs. SDHC. The higher the class the faster the card. Class is a multiplier of 150 kB per sec...the same as CD-ROM drives. Class 2 is the slowest, and class 6 much more desirable obviously. Class 8's are out there, and 10 is coming...eventually...but hopefully you have a fat wallet!