(Relatively) slow performance over GigE

Hi,

I have two servers running Windows 2003 Enterprise, and have been doing
some benchmarking using several tools (Iperf, Netperf, and TTCP) of the
GigE interfaces (Intel 1000).

Each server has a GigE NIC, and I have the NIC from one server connected
to the NIC on the other server via a fiber cross-over cable.

The testing that I've done indicates that I'm only getting about 300
Mbits/sec, and I've been trying to determine what's wrong and how to
closer to the potential Gigabit performance.

I've tried setting the "Jumbo Frames" option in the drivers on both
servers to various sizes, up to 16K, but that actually seemed to make
things much worse, so I've been searching trying to find information on
tweaking my network performance under Windows 2003.

If anyone has worked with GigE under Windows 2003, and been able to
tweak things to get good performance, can you please post how you
accomplished this?

Thanks in advance,
Jim