Ok, I'm installing Debian (Woody) on an IBM Thinkpad A21m and things are going great. By default it installs with the 2.2.20-idepci version of the kernel.

Thinking that higher numbers are better, I installed kernel-image-2.4.24-1-686 (initrd.img). This works well too, no errors on startup.

However...

... the network runs at, like, 1/1000th the normal speed. Both sending and receiving.

Reboot with 2.2.20 and it runs fine again.

For instance, using NFS file copy,
... 2.2.20 copies 8,462,336 bytes in 10 seconds
... 2.4.24 copies 61,440 bytes in the same amount of time

The built-in network is an eepro100.

The output from lspci -vv under both kernels is identical (except 2.4 adds [size=] to everything).

Have reinstalled the machine twice and built the kernel from source once but can't seem to affect it.

Don't know where to go from here.
Cha'.

first don't use generic kernel image unless your really want to drive into troubles. Use SOURCE. image/packaged kernel are slow, not optimized and supporte everything (including thing that are often conflicting together)

lspci -vv will show you the same thing on both kernel btw, try lsmod instead, maybe the 2.4 kernel use a wrong network card drivers.
I suggest you to add paranoid log to syslog and to see if you get any error about your network card.
Btw, about NFS, make sure your client and server use the same version of that thing... I don't trust NFS at all and backward compatibility could be somehow sucky

Ok. I'll try building from source again. Not sure if I've quite figured out the modconf application. When you select a module, does it apply to the currently running kernel or to all kernels you boot from?

lsmod on the 2.4 kernel shows maybe twice the number of modules as 2.2 kernel. I've tried unloading any that aren't in use to see if it makes a difference... none. Both kernels are using eepro100 module for the network card.

Just tried running from a 2.6 kernel but the eepro100 module returns "Unrecognized Kernel" and won't start.

I will enable paranoid mode for syslog and check it for errors (once I figure out how).

Thanks for the help.

lol, as I said, you big sloppy generic 2.4 kernel is probably loading tons of thing you don't need.

About paranoiac log, just take a look at /etc/syslog.conf (or man syslog.conf) and add a line like "*.* /var/log/mylog"

Oh and, don't try 2.6 kernel unless you feel very geek, this kernel is very new and need some more configurations and some apps to be installed.