Kingston Ultimate SDHC Cards

I recently bought one of Kingston's 8GB Ultimate 133x SDHC as it was cheaper than a Sandisk Extreme equivalent. Then I noticed a Kingston 8GB SDHC Ultimate 100x which was described as having the same performance i.e Class 6 20mb/s as the Kingston 133x.

Has anyone got either of these to say whether performance is noticeably different between the two? I'll be using them in a K-5 for the majority of the time.

Thanks

Rob