LTSP client watch youtube video very slow topic

Hello, I just install Ubuntu 14.04 LTSP Server following in this TUT

http://ubuntuforums.org/showthread.php?t=2173749

- Everything good. I create vmware machine as client but When I watch video on youtube, the motion lagging like time lapse video.
- My network switch is 100Mbs
My Server system hardware:
core i5 430M
Ram 4GB
VGA: NVIDIA GeForce GT 330MThank you.