[CentOS] confused with 2 boxes centos 5

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