Why would you want to benchmark the performance of a flash card? If you suspect that the card you have is fraudulent, especially if you didn't buy it from a reputable retailer, these programs will confirm the performance characteristics of the card. Take the result generated from one of the following benchmarking programs below and compare it with the industry standards. For example, for SDHC cards, compare the measured speed of your card with the speed of the class specification of your card. For example, a Class 10 card should achieve somewhere around 10MB/s.
Here are two utilities I have used for benchmarking the speed of a flash card. These utitlies run standalone and does not require an installation on your computer. One utility is called H2testw. The page is written in German and Google Translate is used to translate the page to English. The other utility is called HD_Speed.