I have tried 3 different ethernet cards, a tulip, an eepro100, and a 3c59x. I cannot get more than about 11Mb/sec out of them. At 11Mb/sec, /var/log/syslog fills with this: May 2 17:51:57 i5 kernel: Undo loss 10.10.220.101/3419 c2 l0 ss2/2 p0 May 2 17:52:00 i5 kernel: Undo loss 10.10.220.101/2634 c2 l0 ss2/2 p0 May 2 17:52:00 i5 kernel: Undo loss 10.10.220.101/3228 c2 l0 ss2/2 p0 May 2 17:52:06 i5 kernel: Undo loss 10.10.220.101/4646 c2 l0 ss2/2 p0 May 2 17:52:06 i5 kernel: Undo loss 10.10.220.101/4647 c2 l0 ss2/2 p0 May 2 17:52:09 i5 kernel: Undo loss 10.10.220.101/4222 c2 l0 ss2/2 p0 May 2 17:52:09 i5 kernel: Undo loss 10.10.220.101/4524 c2 l0 ss2/2 p0 May 2 17:52:14 i5 kernel: Undo loss 10.10.220.101/4520 c2 l0 ss2/2 p0 10.10.220.101 is the machine I'm testing from. The message appears from any machine I'm testing on. All machines are plugged into the same switch, and forced to 100/full. I have no problems with my 2.2 kernels, only the 2.4 kernels. Does anyone have any ideas? Jay