Do you use real-crossover cables, or rely on auto-crossover?

I just tried popping an old D-Link 530 card in my box, but Linux really doesn't like having both ethernet cards connected to the same subnet... I suppose that's a real no-no? I was planning on putting the 10/100 on the 10/100 router, and the Gigabit to the switch, and run the Trio server off the 10/100 link (192.168.0.6), and file-server off the gigabit (192.168.0.5). Not possible?

-Dan
PS: Thanks for replying. Felt kinda lonely here today! :-).