Why ue4 develop every operation very slowly

one year develop base this engine,i cannot stand its slow at all,every operation,such as saving map,took 5 minutes,compiler c++ code,took 5 minutes,even i alter only one float varible,load map start the editor,94% wait for half hour,etc
computer i7 4790k,32 gb ram,512gb ssd,even slow
i have develop on unity for three years before,company ask for me use uneal to work and make vr software,i stand it for one whole year be tortured,every day 8 hours worktime,over half of my work time spend on waitting and editor progress not responding,every night and holiday i extra work,my life and my health gone,only for complete my work,write this question i have quit office at the same time.