It's probably due to CD-ROM drive spin-up. After loading enough data to play 10 seconds of movie, after a second or two the drive spins down. When the data buffer is empty 10 seconds later, it tries to read from the disk but since the disk isn't spinning it has to wait for the disk to spin up again.
Real Playstations keep the disk spinning all the time.
There are two solutions to this:
- Make and use an image (that's what I do) with the Mooby2 CDR plugin
- Get Nero DriveSpeed and set the spindown delay to a ridiculously high number, like 86400 seconds (1 day)
Dan