Use your new card with the camera set to record 640 x 480.
If it works OK, then your new card is too slow.
High Definition video requires a fast processor in the camera and a fast memory (which is your card).
The Sandisk Extreme III gets good reviews for speed.
I am using a Kodak Zi8 digital video camera. I purchased a 32GB SDHC card on Ebay. I am having problems with this SD card not working properly. I have taken 19 separate videos making up a total of about 750mb and the camera shows a yellow triangle with an explanation mark in it. I can use a 2GB card without any problems. I am running a test video and it is currently at 37 minutes. Has anyone else encountered this problem? I contacted Kodak support and was told they would give the info to their tech support. Not much in the way of solutions. Kodak states that this video camera will support a 32GB SD card. Thanks in advance, WolfpackRon.