Hi,
Another issue if you set manually will be Duplex mismatching.
Read this about the impact of duplex mismatching...
A duplex mismatch occurs when two connected devices are configured in different duplex modes. This may happen for example if one is configured for autonegotiation while the other one has a fixed mode of operation that is full duplex (no autonegotiation). In such conditions, the autonegotiation device correctly detects the speed of operation, but is unable to correctly detect the duplex mode. As a result, it sets the correct speed but starts using the half duplex mode.
When a device is operating in full duplex while the other one operates in half duplex, the connection works at a very low speed if both devices attempt to send frames at the same time
Best wishes,
Ganesh.