Network Help

[Victor Farah]

Hello,
I have a machine setup with FreeBSD 6.3-PRERELEASE setup on a 
10/100/1000 switch.  There are a pair of em interfaces, and the network 
traffic on this machine is very spuratic.  Both EM interfaces reach 
100Mbps and falls to 5~10Mbps, the very next minute, the traffic is very 
spuratic.  The media of the interfaces is as follows:
EM0: media: Ethernet autoselect (1000baseTX <full-duplex>)
EM1: media: Ethernet 1000baseTX <full-duplex>
Currently the EM1 card is in use.
I watch an MRTG that I have setup to see the machine failing at 
sustaining its bandwidth.
I have 13 other machines setup the same way but traffic is running fine 
and working very well, the only difference between those and the new 
one, is that it's pushing much more data through it; almost the same 
amount of data the 13 other machines push combined.