You should follow
VANN suggestion about hardware
would like to make my ROI fast?
please help me what build is profitable with free electricity?
with free electricity you should be good , the question is, is your ROI .
Dont forget about a few very important things :
None of those calculators you are seeing on the web can tell you what's coming tomorrow , months later or 6 months later !
Those calculators telling you about today , at that moment when you typing in your information !
No one can tell you how much profit you going to be able to make !
No one can tell you it's going to be profitable for you or not !
No one can tell you for sure what's going to happen with cryptocurrency ,
....price might going down or up ,
....difficulty is going up as more and more ppl get into mining ,its mean you going to mine less and less coins ...