Seeing the mention of the 3C501 made me dig up old Linux source to find the amusing comments in "drivers/net/3c501.c":
Do not purchase this card, even as a joke. It's performance is horrible, and it breaks in many ways.
...
The driver is less efficient than it could be. It switches through receive mode even if more transmits are queued. If this worries you buy a real ethernet card.
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The driver still allows only the default address for cards when loaded as a module, but that's really less braindead than anyone using a 3c501 board. :)
Do not purchase this card, even as a joke. It's performance is horrible, and it breaks in many ways.
...
The driver is less efficient than it could be. It switches through receive mode even if more transmits are queued. If this worries you buy a real ethernet card.
...
The driver still allows only the default address for cards when loaded as a module, but that's really less braindead than anyone using a 3c501 board. :)