I've cleared A to F in 45 mins in the past, but I'm done attempting to book close connections in PHL with an international leg. Last week I was MBJ-PHL-BOS on a Sunday afternoon with a 1.5 hr layover to make it to B. I didn't even come close to making my flight. I think I was #100 in line trying to reclear security when the doors closed. Luckily PHL-BOS is basically a shuttle that runs every hour. If I had a destination that US didn't run on a regular basis, I'd rather book the later flight than chance it.