If you have loaded your animation then several more then try to run the first one and it is reloading the files then yes you have hit the cache limit. I truly forget what that size is on the Vision.
On a Carbonite: I have not used the PNG file type, however I have used the TGA file type and mathematically you can get 392 frames of HD video onto a media player. To figure it out we had to look at the size of one TGA file, then divide 4GB by the file size, thus giving us the maximum amount of frames that could be loaded onto a media player before it started to overwrite the RAM with different information. It depends on the file type and also if you are in a SD or HD state. You just have to remember you only have 4GB per pair of media players.
I think the cache limit is the same for both switchers (if not - probably real close)
#Vision