Over the last couple of weeks we have seen three different machines "crash" 
with 

NMI:... going to debugger 
kernel: type 265 trap code 0

Two machines are brand new DELL Optiplex GXpro (Pentium Pro 200) with
ECC memory, the third is an Intel Venus motherboard again PPro200 with
ECC memory.

In two out of three cases ( I didn't check the 3rd) callout shows

1	1	0x0 _nfs_timer
2	1	0x0 _roundrobin
2	0	0xf88c6000 _tulip_timeout_callback

It is highly likely that there was heavy nfs traffic going on at the
time of thse crashes?

Both these machines are still in the debugger - Any clues on how to
diagnose further? 

Should I suspect the network Interface card?

Many thanks for any help.

Tim.