APM problems with 3c509B

[Borries Demeler]

I noticed one particular strange effect of APM:

When I turn on APM in the BIOS on my Supermicro P6DBS the 3C509B Vortex
drops ping rates dramatically to the point where it doesn't answer at all.
After a cycle of APM invocation, the ping rates drop to 200-300 ms,
after I do "ifconfig eth0 down ; ifconfig eth0 up" they go back to normal
(< 1 ms). I changed from autosensing to 10 MB (on our current switched
network), but that didn't seem to make a difference. I am using slackware
3.6, 2.0.36 with 3c509.c-0.99H

-Borries