Finally I found the problem:
I encoded a sample video at 250, 500, 750, 1000, 1250,1400, 1500 bitrates...
Using bitrate 1500 or higher the freeze appear... bitrates below 1500 are safe.
Im speaking about AVI files!!! .. I can play monster MP4 1080 movies with bitrates of 8000 or upper without problem through the USB
EDIT.-
I was measurin the HD speeds:
Main system HD 26 Mbytes/sec (avis with high bitrate work)
External USB HD 33 Mbytes/sec (Avis with high bitrate freeze)
So its not a problem about the data transfer speed or USBs running in 1.0/1.1 mode
Guys,, any clue?
in 2001 Divx movies were very popular.. maybe M$ added a antipiracy limitation in XPsp1 to avoid watching high bitrate Divx movies though external devices (CD/DVD/USB)? (remember that this problem is also present when playing video through CD or DVD