| I've seen something similar before, but I'm not sure it'd apply to the setup you're having problems with.
When dealing with some Sun blades and Cisco switches, there was a negotiation problem where the Ciscos would negotate full duplex, and the Suns would negotiate half duplex. The end result was a somewhat intermittent drop in response time. It didn't help that we were load balancing across about four web servers, as it made it difficult to tell where the problem was.
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