[RFC] Poor Network Performance with e1000 on 2.6.14.3

My configuration is two Dell Optiplex PCs ( /proc/cpuinfo attached)
connected back to back.. I am using the vanilla 2.6.14.3 kernel, and
using the e1000 driver for the onboard Intel PRO 1000 Ethernet Card on
both machines. I am performing  both Full and Half Duplex Data
Transfer  and the figures which I am getting are abysmal..

Full Duplex Data Transfer ( Both send and receive )
Ettcp Send  - 55167.45 KB/sec
Ettcp Receive - 54902.49 KB/sec
Total Throughput ~ 110MB/sec
CPU IDLE - 55 percent

Half Duplex Data Transfer ( Sending from one host to another )
Total Throughput = 103 MB/Sec
CPU IDLE - 65 percent

Now, I assume that on Gigabit ethernet, I should be getting Line Rate,
which is around 220 MBps. Even the CPU is not getting max-ed out here
and I am at a loss to understand this behaviour.

Please find the ethtool dump, and the ettcp send and receive dumps for
both full and half duplex transfers

Regards,
Ashutosh