A strange one here... We've got a WS-C4506 acting as a core with Sup V and line cards WS-X4448-GB-SFP (fiber card) and WS-X4548-GB-RJ45V (gigabit Ethernet card). Our edge switches connect through the fiber card, and we have a few servers plugged into the ethernet card.
Here's the problem: on some (not all) of the servers plugged into the ethernet card, we have some bandwidth issues. When a file transfer is initiated from a PC on an edge switch, we get about 25Mbps download (core to edge) and 90Mbps the other way. However, when the file transfer is initiated from the same server to the same PC, we get 90Mbps both ways. The only difference is which machine initiates the transfer.
This happens with or without QoS. The configuration doesn't seem to matter at all. If I plug the servers into a different switch connected to the fiber blade, then transfers go at full speed both ways.
Does anybody have any ideas?