Rate Froch as a finisher.
Some examples of his show-closing:
Against Bute, he began landing hurtful right hands from the opening round but never forced the issue and punched himself out with any reckless wildness. He worked behind the jab in the 2nd, scoring progressively better and laying the groundwork. He did become an eager beaver when Bute was hurt in the third, and perhaps wasted a chance at a KO3 by allowing Bute to to repeatedly move in and hold every time he opened up with mostly wide combos. Some straighter shots, and Bute would never have escaped as he was initially hurt only a minute in. He was more disciplined and patient in the fourth, and continued to widen the dent. This allowed him to get down to business early in the 5th and put the kibosh without much delay.
Against Taylor, he scored the accumulation knockdown with a minute left in the 12th and set to work as soon as the ref motioned to continue. Even visibly exhausted, he put shots together with increasing force and frequency and distributed to head and body until Jermain was vanquished - and did so in the nick of time with less than twenty seconds to go. Any further delay in letting his man hang around and Froch would have lost a decision.
Against Magee, he caught the tiring southpaw stepping forward lazily about a minute into the 11th with a big right hand and didn't fail to notice how much it shook him. Magee was then very economically KTFO as Froch came on and put everything he had into a big wide blocked left hook and the big right uppercut that did the job.
He just has those instincts.
Go back six years to when he first began to step up in class (to at least top-line domestic level, if not world), and look at who he has stopped and failed to stop.
7 of 13, 53% and that's after weaning off baby food in terms of opponent quality.
The six x's are guys you don't really expect anybody to stop: Dirrell being notoriously ultra-negative and possessing the athleticism to go largely untouched, and the rest - Pascal, Kessler, Ward, Johnson, & Abraham - renowned for their rugged durability. Glen Johnson just might be the toughest of the bunch and he's the only one with a stoppage loss.
IMO, his ability to show the exit door to anyone he hurts (and the way he fights - ever aggressively stalking and coiled to strike, true to his namesake - he's inevitably going to hurt anyone who isn't hard as nails or a defensive wizard) is his most valuable asset. Or chief among them, at the very least...up there with his heavy hands, chin, and stamina. In all these dangerous qualities he more than makes up what he lacks in speed or technical finesse, and even there he isn't quite a caveman as his schooling of Abraham demonstrated.