Sorry to jump in so late, but,
I know a guy who won't post here, he has an A3000 with CSPPC, 604@233. He is having the exact same issues with networking. I am not. I have an A3000 with CSPPC, 604@200. I cannot duplicate his/your problem no matter what.
In case you didn't read my other thread, I have 70ns SIMMs. I made sure the setting was 70ns before installing OS4. After installing, OS4 was very crash-happy. For no good reason, I switched my setting to 60ns, and OS4 has been very stable ever since!