a neat solution
Basically, if you run insmod -f nvnet, the driver is loaded. But the startup scripts don't want to run "insmod -f", so you may be tempted to put it in rc.local.
However, there's a neat solution to it. Don't modify rc.local. You can still trick your startup scripts to force the module insert.
Just add this line to /etc/modules.conf:
install eth0 /sbin/insmod -f nvnet
This way, when the startup scripts try to install the nforce module, they are told to actually attempt a forced insert.
Also, make sure you have this line in modules.conf:
alias eth0 nvnet
(but that should be added already by the nforce driver RPM)