brandon thanks for the response. Actually in my research that was suggested and I verified all of that. I also ran Wireshark and there was little packet loss or retransmissions. However, I did manually add up the bytes/sec on each port in the GUI (sure a laborious way to do it since you can't access the CLI on these low-end switches). From the specs for this switch it supports up to 52Gbps. My calcs showed the ports totalled about 120Gbps. I would assume this means the switch doesn't have the horsepower which is not really obvious until I try to copy a large file. It was perplexing that capacity tests at ISPGeeks showed no bandwidth issues.

I think the screen shot you showed is total bytes and packets for the interval since the counters were last reset, not per second statistics.  So, I don't think you can calculate from that information how much backplane capacity is being used.

That said, what is your WAN link speed and what are your expectations for transfer speed total and per device?  You are correct, this is a low end desk top switch and may not be appropriate for your application or expectations.

I refreshed those port speeds several times and they stayed about the same. As far as the WAN link it is 100MBps. Calculations show they should theoretically reach close to 10MBps but file transfer speeds are in the kbps range.