ok i was facing this issue and also i read about all other things on internet but none of them worked for me and by just tweaking here and there i got on the feature where we can restore editors from previous sessions , to check i turned it off and now code opens very fast like previously it was taking 8 to 12 seconds and giving end process dialog but now it works smoothly and very responsively, i dont know how i opened it but it solved my problem,just see the picture below and add following settings also if you can try to clear previous history