[CentOS] confused with 2 boxes centos 5

Fri May 18 19:28:24 UTC 2007
Jerry Geis <geisj at pagestation.com>

  Hi All,

I had a box centos5 AMD64 X2 4200+, Asus motherboard, Nvidia 7100 video 
card, 512M,
when playing a video at 1080p it did well but had a couple times went 
out of sync.

So amd dropped its price and I got a 5200+, gigabyte motherboard, Nvidia 
7100 video card, 512M.
This FASTER system is actually slower. The video is WAY behind on sync.

I have looked at the X config they are the same.
I have the same mplayer version
I have the same centos 5 version
The CPU usage is actuall below 60.
I ran "cpuspeed -C &" on both boxes

/proc/cpuinfo on both boxes report the correct values.
4200+, 512cache, clocked at 2200
5200+ 1024 cache, clocked at 2600

What can be causing the faster machine to SUCK so bad at playing the 
video back?
THanks,

Jerry