Cain will overwhelm Overeem with his pace and finish him via TKO at late 2nd or 3rd round.
Overeem only chance is to stand with Cain and knock him him out but i wouldnt count on that. He is more of a counter striking guy and Cain WILL take him down and GNP his ass. Unlike JDS, Overeem won't be able to work his way back up his feet (even if he can, look what happen to JDS).
I Cain taking this by demolitioning the demolition man.