The Falcon Heavy has three times the initial thrust, three times the booster weight, but only the normal amount of second stage weight. Going by numbers from Wikepdia that don't count the payload the normal Falcon 9 has a TWR of 1.41 and the Falcon Heavy has one of 1.64. So it should be lifting into the air about half again as fast.

The payload weight will make a small difference but it'll be pretty small to the overall weight in any event and not make a large difference. Arabsat-6A is just 6 tons compared to a total weight of 1426 tons.