if they are at default, they are much different! ;-)
you should have as default 8192 for both send receive buffers ... rise to 32768 both
clusters and Max mem as well ... that value are too small for modern/ish connections
These settings are different accordingly on what NIS card/driver/connection speed you have.
Thats seems ok for WAN and a 10 Mb NIC card, even if a bit high for LANs
Hence you have to experiment a bit