OK, re laptop I can confirm the network adapter on the laptop wont go faster than 100mbs so I can discount this device as a bit of test gear. The other thing is that one of the two switches will not output anything exceeding 100mbs on any of its 8 ports no matter what connects to it. Therefore, unless my maths are all wrong, if a device capable of outputting data at say 300mbps connects to a device that can only handle 100mbs, then surely the throughput will be reduced accordingly. The output from the Hub is via an ethernet cable (flat ribbon type) and connects to one of the ports on the 10/100 switch. Six other ports are connected to various devices as mentioned previously. The eighth is a 30ft link ethernet cable to another switch in another room. (Cat 5e I think - will need to check). This switch is 10/10/1000 capable. So - the first switch can only output data at 100mbs rate maximum so data being sent along the link cable also will peak at 100mbs (unless I'm all wrong on this, although this theory seems to be backed up by the state of the100mbs LED on the port that has the link cable connected which is the only one lit . All the others have two LEDs lit which indicate full 1000mbs capability). Further to this, would I be right in assuming that data from the Hub trying to send at breakneck speed from one of its three ports to the switch via the flat ethernet cable will also have to seriously renegotiate its speed as the switch cant handle anything more than 100mbps.
Anyway, I will swap out the 10/100/1000 switch tomorrow and see if it makes any difference. If I'm right about speed negotiation, then throughput should increase considerably. If I'm wrong, I've just wasted a few quid on a new switch. Story of my life!