Sounds like a network driver or settings issue. Sometimes it helps to
set correct values for MaxMTU on all systems. If this doesn't help you may need to experiment with other network drivers or network (adapter) settings. First thing to do would be to find out which system is causing the issues. To rule out your homeserver and router try a large file transfer from another client which has a wired connection. If that works try a wire connection for the Thinkpad. If that also works it's an issue with either the network adapter driver or settings on your client, or the (wireless) network settings on your router.