Why does inc R of a RL circuit increase dVL/dt. Here I have circuits and details
The thing which caused the speedup was the increase of voltage, not the increase of resistance. If the resistance were zero ohms the current would grow infinitely with growth rate = voltage divided by inductance. That gives amperes per second if the inductance is in henries.

The series resistor gives a limit to for the current. In both cases that limit is the same, but the initial growth rate, when the voltage loss in the resistor is small, is 50 amperes per second with 50V supply and 5 amperes per second with 5V supply. 

As the current increases, the growth rate decreases because there's less voltage left over the inductor, the resistor voltage loss = IR.