playing image and difficoult to have costant 25.0 fps

[samsc]

I know this is not software bug because same problem i have if start
directly file from quick time,the image go on step by step.
The same files i checked on similar MAC G5 2.0 gigahertz with
GEFORCE 550 and 64 Mb without problem.

if this happens in quicktime... as you say here... - it means you have probably got an uncompressed movie- or a movie in a codec which needs more resources to playback.

before you do anything else ----

You need to give me the movie properties information - such as codec, image size etc.

please open up the movie in quicktime player - and check for you and me the type of movie file using "Show Movie info"