Compiling and running a kernel with -O2 -mbwx makeoptions did help out 
with ethernet
performance, however, I'm still seeing these messages during high I/O.  
This is
a 2.0G kernel.  Let me know if there is more information I can provide 
to help resolve
this.

Jul 21 02:24:20 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 02:24:29 vinland /netbsd: fxp1: device timeout
Jul 21 02:24:32 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 02:24:35 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 02:24:40 vinland /netbsd: fxp1: device timeout
Jul 21 02:24:44 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 02:25:00 vinland /netbsd: fxp1: device timeout
Jul 21 02:25:06 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 02:25:17 vinland /netbsd: fxp1: device timeout
Jul 21 03:35:23 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 03:35:34 vinland /netbsd: fxp1: device timeout
Jul 21 03:35:38 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 03:35:46 vinland /netbsd: fxp1: device timeout
Jul 21 05:19:03 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:13 vinland /netbsd: fxp1: device timeout
Jul 21 05:19:18 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:22 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:27 vinland /netbsd: fxp1: device timeout
Jul 21 05:19:32 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:35 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:40 vinland /netbsd: fxp1: device timeout
Jul 21 05:19:43 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:47 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:19:52 vinland /netbsd: fxp1: device timeout
Jul 21 05:19:58 vinland /netbsd: fxp1: WARNING: SCB timed out!
Jul 21 05:20:07 vinland /netbsd: fxp1: device timeout

Name  Mtu   Network       Address              Ipkts Ierrs    Opkts 
Oerrs Colls
fxp0  1500  <Link>        00:02:56:00:0f:ad 215107308     0 35744011    
  0     0
fxp0  1500  10/8          vinland1          215107308     0 35744011    
  0     0
fxp1  1500  <Link>        00:02:56:00:0f:ae 88755565     0 15060941    
14     0
fxp1  1500  192.94.73/24  vinland.freeshell 88755565     0 15060941    
14     0
lo0   33136 <Link>                                38     0       38     
0     0
lo0   33136 loopback/8    localhost               38     0       38     
0     0

fxp1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
         address: 00:02:56:00:0f:ae
         media: Ethernet 100baseTX full-duplex (100baseTX 
full-duplex,flowcontrol,rxpause,txpause)
         status: active
         input: 88755719 packets, 125857606227 bytes, 168194 multicasts
         output: 15061037 packets, 3018509616 bytes, 14 errors
         inet 192.94.73.6 netmask 0xffffff00 broadcast 192.94.73.63