What is a major limitation when using standard Ethernet in a heavily loaded network?

When standard Ethernet is used in a heavily loaded network, a significant limitation is the higher collision rates. Ethernet operates on a shared medium, particularly in traditional hub-based networks or when using a bus topology. In such environments, multiple devices try to communicate over the same channel, leading to data collisions when two or more devices transmit simultaneously.

When collisions occur, the affected devices must stop their transmissions and perform a backoff algorithm before attempting to retransmit. This not only delays the individual devices but also contributes to overall network inefficiency, as the available bandwidth is consumed by these collisions rather than productive data transmission.

While the other options, like lower bandwidth capacity, incompatibility with digital signals, and increased latency, are important considerations in networking, they do not directly address the immediate impact of network congestion and competition for bandwidth that results in higher collision rates impacting performance in a heavily loaded Ethernet network. High collision rates can severely affect the network's throughput, making it a primary concern in such scenarios.