The only affect different computers may have is their NIC speed. You could have NICs that run at 10/100/1000 running on a bus and they will communicate at the highest common speed of 1000 Mbps. If you add a NIC to the bus that only runs at 10 Mbps, it slows the entire segment down to 10 Mbps.
would computes need to be identical on a bus Network
The only affect different computers may have is their NIC speed. You could have NICs that run at 10/100/1000 running on a bus and they will communicate at the highest common speed of 1000 Mbps. If you add a NIC to the bus that only runs at 10 Mbps, it slows the entire segment down to 10 Mbps.
A point-to-multipoint network looks the same as a star network.
The physical topology is similar, but the operation of the two is quite different.