Some more information:

Replication is preformed on a separate nic.

Load is also very low < 0.2

Ram:
Used memory (MB): 372.53
System cache (MB): 1585.34
Physical free memory (MB): 66.46

Used swap size (MB): 44.10
Free swap size (MB): 4051.89

Network controllers
Intel Corporation 82573E Gigabit Ethernet Controller (Copper) (rev 03)
Intel Corporation 82573L Gigabit Ethernet Controller

Network drivers:
Ethernet Channel Bonding Driver, v3.1.1
Intel(R) PRO/1000 Network Driver