A4K freezing up when using MiamiDX

[Ideal]

So.. I have an Amiga 4000 with a mediator Di and a realtek 8139.
If I start up Miami DX and click online it sometimes freezes up. Then sometimes it gets past that. So if I open aweb and type google.com it will load up google for about 1 second and then freeze up the Amiga.
Which seems to me like activity on ethernet = machine freezes up.

Does anyone have any suggestions?

[Ideal]

Now typing on Amiga.
Fast ethernet seems to have been the problem. Changed no settings only switched to x-surf.device, after plopping an x-surf in there.
So clearly fastethernet was the issue.