Use the W5100 module instead (if you need ethernet)
Good idea, thanks! Same code, but only W5100 based:
Sketch uses 17190 bytes (...) Global variables use 853 bytes (41%)
Using W5500 ( Ethernet2.h ) gives even better:
Sketch uses 14712 bytes (...) Global variables use 809 bytes (39%)
If you don’t need ethernet, use usb or wifi since those options also use less ram.
I need some kind of 25m wire so options are ethernet, RS-485 or PJON