328PB reset pin not needed.. What do to?

[gitduino]

2 questions:

1. So, in a custom build where the MCU has been programmed and permanently
   soldered to the board, obviously there wont be no reset button required.
   Thus, after some research I came across several advices that suggested that the unused RESET pin should be pull-up with a small value capacitor 100nF to ground.
   I was wondering if this is fine ?? see image.
   

   

2. when operating at 3.3V, is the MCU much slower in waking up than another operating at 5V ??
   I noticed some performance difference when operating the 328PB at 3.3V 8MHz vs 5V 8MHz.
   You heard right, I’m comparing 2 different voltages at 8MHz
   To me, the latter seemed more robust and faster in response compared to the 3.3V

regards,
John