> Don't know whats up with ex but I never got a decent performance out of 
> that driver on the Qube2.. the 3c905C have excessively poor performance 
> on the Qubes. They seem to be able to use Tx properly, but Rx is quite a 
> bit slower than 100 KB/s...

Do you have proper MII devices in your kernel config?
I think 3C905C requires exphy(4) or bmtphy(4), and
a wrong MII device (generic ukphy(4) is used in that case)
could cause such awful performance, as I wrote.

"dmesg might help."

> So far a cheap D-Link DFE-530TX (via-rhine) performs much better than 
> the 3Coms on these... it should be the other way around :-D

BTW, vr(4) can't DMA to/from unaligned buffers both on TX and RX,
so it would have less performance even on i386.
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Izumi Tsutsui