[Kushan]

I would be surprised if the SH itself was limiting bandwidth on specific ports. You could always test that theory by swapping the cables around and seeing what happens. If it is still affecting specific machines then something is going on with those machines.

You do seem to be using a lot of devices with the SH though, I'm not sure how well it copes. The SH2 is by and large decent but you might be better off with a solid router instead.