FC2T3 - NFS throughput problem
 

I have a FC2T3 nfs server and a RH-9.0 nfs client, both connected to a gigabit switch.
Trying to write a large file (dd if=/dev/zero of=big500 bs=1M count=500) to the nfs
server, the copy process takes minutes or infinite time. Doing the same test, but using RH-9.0 (same hw) as the nfs server, the copy process takes ~10 seconds.
Taking a tcpdump, I get lots of 'slsfs.nfs: 1472 write fh Unknown/0100000200080005D5700A008A710A0084A75613D5700A0083A4A98000000000 4096 bytes @ 0x1d3d000 <unstable>'.
I also tried to increase rmem_default and rmem_max to 512k - no change.
Hardware: Dell PE2650, Broadcom Corporation|NetXtreme BCM5703X Gigabit Ethernet
NIC driver: TG3
I was also going to test the Broadcom driver, but failed on 'bcm5700: Unknown symbol genapic'
Kernels test so far (nfs server): 2.6.5-1.358smp and 2.6.5-1.327smp