I have one of those switches here except the 16 port version.
I believe there's updated firmware on 3com's website for them. You'll want that. For optimum network performance you want to set every device you have, if it supports it, to 100MbFDX and then set each switch port to the same. If the device doesn't support it, leave it in Auto-negotiate mode.
There's a trick on those switches that the other 3com products don't do. When you get all your ports configured, you have to hit Save Configuration, or else when you power it down, everything is lost. Other 3com products save the config when you make the change, but that one only stores it. When I first got one in, I assumed the "save configuration" button downloaded a copy of the config for later upload.
They're ok managed switches, I put the one I have in the maintenance shop so if it gets destroyed, I'm not out a bunch of cash. It's currently mounted against the wall behind a book case, but it's loud as hell.