thanks folks.

The 7600 has at least 256MB L2 Cache. The 5500 is... stock, so whatever was standard (I can't remember)

Next question; what codec do you use? The list is so long. Motion-JPEG seems to give good results.

I don't care about file size, I can move the movies to a faster Mac and compress the video later... I just want it to capture as best as it can. Anyone else around that used to use Adobe Premiere or Avid Videoshop?