has none but there must be some fancy new way of dealing with them that the atmeaga doesn't have.
Well that is down to the compiler to use if it has one. Not much you can do about it unless you want to hack the compiler.
The simple fact of having 32 bit registers is going to give you a minimum of a 4X time bonus, so add that to the 5X processor speed and you get a minimum of 20X.
Also ARM chips have a barrel shifter so that means if you want to shift something 10 places to the left that takes one instruction where as on an 8 bit machine it takes at least 10 instructions.